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Sample records for mammographically occult malignancy

  1. Mammographically Occult Asymptomatic Radial Scars/Complex Sclerosing Lesions at Ultrasonography-Guided Core Needle Biopsy: Follow-Up Can Be Recommended.

    PubMed

    Park, Vivian Youngjean; Kim, Eun-Kyung; Kim, Min Jung; Yoon, Jung Hyun; Moon, Hee Jung

    2016-10-01

    An increasing number of radial scars are detected by ultrasound (US), but their management is controversial. This study investigated the upgrade rate in mammographically occult radial scars/complex sclerosing lesions without epithelial atypia at US-guided 14-gauge core needle biopsy in asymptomatic patients. Nineteen mammographically occult benign radial scars/complex sclerosing lesions (median size, 7 mm; range, 3-23 mm) were included. Patients underwent surgical excision (n = 10) or vacuum-assisted excision, with follow-up US at least 6 mo after benign vacuum-assisted excision results (n = 8), or underwent US follow-up for 2 y after core needle biopsy (n = 1). Any cases with change in diagnosis to high-risk lesions or malignancy at excision were considered upgrades. The upgrade rate was 0.0%. Based on US findings, 15.8% (3/19) were Breast Imaging Reporting and Data System (BI-RADS) category 3, 68.4% (13/19) were BI-RADS category 4a and 15.8% (3/19) were BI-RADS category 4b. Follow-up with US can be considered for mammographically occult benign radial scar/complex sclerosing lesions diagnosed by US core needle biopsy in asymptomatic patients. PMID:27444865

  2. Prognosis for Mammographically Occult, Early-Stage Breast Cancer Patients Treated With Breast-Conservation Therapy

    SciTech Connect

    Yang, Tzu-I. J.; Yang Qifeng; Haffty, Bruce G.; Moran, Meena S.

    2010-01-15

    Purpose: To compare mammographically occult (MamOcc) and mammographically positive (MamPos) early-stage breast cancer patients treated with breast-conservation therapy (BCT), to analyze differences between the two cohorts. Methods and Materials: Our two cohorts consisted of 214 MamOcc and 2168 MamPos patients treated with BCT. Chart reviews were conducted to assess mammogram reports and method of detection. All clinical-pathologic and outcome parameters were analyzed to detect differences between the two cohorts. Results: Median follow-up was 7 years. There were no differences in final margins, T stage, nodal status, estrogen/progesterone receptor status, or 'triple-negative' status. Significant differences included younger age at diagnosis (p < 0.0001), more positive family history (p = 0.0033), less HER-2+ disease (p = 0.0294), and 1{sup o} histology (p < 0.0001). At 10 years, the differences in overall survival, cause-specific survival, and distant relapse between the two groups did not differ significantly. The MamOcc cohort had more breast relapses (15% vs. 8%; p = 0.0357), but on multivariate analysis this difference was not significant (hazard ratio 1.0, 95% confidence interval 0.993-1.007, p = 0.9296). Breast relapses were mammographically occult in 32% of the MamOcc and 12% of the MamPos cohorts (p = 0.0136). Conclusions: Although our study suggests that there are clinical-pathologic variations for the MamOcc cohort vs. MamPos patients that may ultimately affect management, breast relapse after BCT was not significantly different. Breast recurrences were more often mammographically occult in the MamOcc cohort; consideration should be given to closer follow-up and alternative imaging strategies (ultrasound, breast MRI) for routine posttreatment examination. To our knowledge, this represents the largest series addressing the prognostic significance of MamOcc cancers treated with BCT.

  3. Characteristics of quantitative perfusion parameters on dynamic contrast-enhanced MRI in mammographically occult breast cancer.

    PubMed

    Ryu, Jung Kyu; Rhee, Sun Jung; Song, Jeong Yoon; Cho, Soo Hyun; Jahng, Geon-Ho

    2016-01-01

    The purpose of this study was to compare the characteristics of quantitative per-fusion parameters obtained from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in patients with mammographically occult (MO) breast cancers and those with mammographically visible (MV) breast cancers. Quantitative parameters (AUC, Ktrans, kep, ve, vp, and wi) from 13 MO breast cancers and 16 MV breast cancers were mapped after the DCE-MRI data were acquired. Various prog-nostic factors, including axillary nodal status, estrogen receptor (ER), progesterone receptor (PR), Ki-67, p53, E-cadherin, and human epidermal growth factor receptor 2 (HER2) were obtained in each group. Fisher's exact test was used to compare any differences of the various prognostic factors between the two groups. The Mann- Whitney U test was applied to compare the quantitative parameters between these two groups. Finally, Spearman's correlation was used to investigate the relation-ships between perfusion indices and four factors - age, tumor size, Ki-67, and p53 - for each group. Although age, tumor size, and the prognostic factors were not statistically different between the two groups, the mean values of the quantitative parameters, except wi in the MV group, were higher than those in the MO group without statistical significance (p = 0.219). The kep value was significantly differ-ent between the two groups (p = 0.048), but the other parameters were not. In the MO group, vp with size, ve with p53, and Ktrans and vp with Ki-67 had significant correlations (p < 0.05). However, in the MV group, only kep showed significant correlation with age. The kep value was only the perfusion parameter of statistical significance between MO and MV breast cancers. PMID:27685105

  4. Versican but not decorin accumulation is related to malignancy in mammographically detected high density and malignant-appearing microcalcifications in non-palpable breast carcinomas

    PubMed Central

    2011-01-01

    Background Mammographic density (MD) and malignant-appearing microcalcifications (MAMCs) represent the earliest mammographic findings of non-palpable breast carcinomas. Matrix proteoglycans versican and decorin are frequently over-expressed in various malignancies and are differently involved in the progression of cancer. In the present study, we have evaluated the expression of versican and decorin in non-palpable breast carcinomas and their association with high risk mammographic findings and tumor characteristics. Methods Three hundred and ten patients with non-palpable suspicious breast lesions, detected during screening mammography, were studied. Histological examination was carried out and the expression of decorin, versican, estrogen receptor α (ERα), progesterone receptor (PR) and c-erbB2 (HER-2/neu) was assessed by immunohistochemistry. Results Histological examination showed 83 out of 310 (26.8%) carcinomas of various subtypes. Immunohistochemistry was carried out in 62/83 carcinomas. Decorin was accumulated in breast tissues with MD and MAMCs independently of the presence of malignancy. In contrast, versican was significantly increased only in carcinomas with MAMCs (median ± SE: 42.0 ± 9.1) and MD (22.5 ± 10.1) as compared to normal breast tissue with MAMCs (14.0 ± 5.8), MD (11.0 ± 4.4) and normal breast tissue without mammographic findings (10.0 ± 2.0). Elevated levels of versican were correlated with higher tumor grade and invasiveness in carcinomas with MD and MAMCs, whereas increased amounts of decorin were associated with in situ carcinomas in MAMCs. Stromal deposition of both proteoglycans was related to higher expression of ERα and PR in tumor cells only in MAMCs. Conclusions The specific accumulation of versican in breast tissue with high MD and MAMCs only in the presence of malignant transformation and its association with the aggressiveness of the tumor suggests its possible use as molecular marker in non-palpable breast carcinomas

  5. Deep venous thrombosis and occult malignancy: an epidemiological study.

    PubMed Central

    Nordström, M.; Lindblad, B.; Anderson, H.; Bergqvist, D.; Kjellström, T.

    1994-01-01

    OBJECTIVE--To determine the risk of subsequent cancer in patients with deep venous thrombosis confirmed by venography. DESIGN--Follow up of all patients who had venography for suspected deep venous thrombosis during 1984-88. Patients were traced through a cancer registry up to 1 January 1991. SUBJECTS--4399 patients who had phlebography in one hospital. SETTING--General hospital in Malmö, Sweden, serving a population of 230,000. MAIN OUTCOME MEASURE--Number of cancers recorded. RESULTS--4399 patients had venography for suspected deep venous thrombosis; 604 were known to have a malignancy at the time of venography and were excluded from further analysis. 1383 had deep venous thrombosis, 150 of whom subsequently developed cancer. 182 of the 2412 patients without thrombosis developed cancer. During the first six months after venography 66 patients with thrombosis developed malignancy compared with 37 patients without thrombosis (P < 0.0001). 38 of the cancers in the deep venous thrombosis group were detected by history, physical examination, and laboratory tests. Three patients had postoperative or post-traumatic deep venous thromboses. Only two of the remaining patients would have benefited from early detection by extensive screening. After six months the incidence of cancer was identical in patients with and without thrombosis. CONCLUSION--Deep venous thrombosis is associated with a significantly higher frequency of malignancy during the first six months after diagnosis. Malignancies can be found with simple clinical and diagnostic methods and extensive screening is not required. PMID:8173368

  6. Diffuse Arterial Thrombosis as a First Manifestation of Occult Malignancy

    PubMed Central

    Kotlar, Irina; Antova, Emilija; Kedev, Sasko

    2016-01-01

    Aim. To raise the awareness of a hypercoagulability state as it is often associated with the different types of malignancies. Venous thromboembolism is a frequent complication in these patients, and usually it happens after the diagnosis of cancer is confirmed. However, hypercoagulability disorders presenting as the first symptoms or signs in the cancer patients have rarely been reported. Furthermore, arterial thrombosis is extremely rare even in cancer patients. Method. Review of the case characteristics and literature review. Results. We present a case of 39-year-old woman who was admitted to our hospital because of intermittent claudication in the right lower extremity. CT angiography revealed multiple thrombi in the arterial system starting from the left ventricle, followed by a thrombus in the distal part of the descending aorta, in the superior mesenteric artery, and in the right popliteal artery. Further investigation of this young patient with no risk factors for hypercoagulable state and no other comorbidities led to complete work-up including diagnostic evaluation for malignancy. The suspicion was confirmed after performing upper endoscopy with biopsy, which revealed malignant neoplasm of the stomach. Conclusion. Whenever a patient suffers hypercoagulability disorders, even arterial thrombosis, we should always consider the possibility of a cancer. PMID:27799941

  7. Reliability of Breast Ultrasound BI-RADS Final Assessment in Mammographically Negative Patients with Nipple Discharge and Radiologic Predictors of Malignancy

    PubMed Central

    Park, Chae Jung; Kim, Eun-Kyung; Moon, Hee Jung; Yoon, Jung Hyun

    2016-01-01

    Purpose The purpose of this study was to retrospectively investigate the reliability of breast ultrasound (US) Breast Imaging Reporting and Data System (BI-RADS) final assessment in mammographically negative patients with pathologic nipple discharge, and to determine the clinical and ultrasonographic variables associated with malignancy in this group of patients. Methods A total of 65 patients with 67 mammographically negative breast lesions that were pathologically confirmed through US-guided biopsy were included. Results Of the 53 BI-RADS category 4 and 5 lesions, eight (15.1%) were malignant (six ductal carcinomas in situ, one invasive ductal carcinoma, and one solid papillary carcinoma). There was no malignancy among the remaining 14 category 3 lesions. Malignant lesions more frequently displayed a round or irregular shape (75.0%, 6/8; p=0.030) and nonparallel orientation (33.3%, 4/12; p=0.029) compared to the benign lesions. The increase in the BI-RADS category corresponded with a rise in the malignancy rate (p=0.004). Conclusion The BI-RADS lexicon and final assessment of breast US reliably detect and characterize malignancy in mammographically negative patients with pathologic nipple discharge. PMID:27721881

  8. Computer-aided characterization of malignant and benign microcalcification clusters based on the analysis of temporal change of mammographic features

    NASA Astrophysics Data System (ADS)

    Hadjiiski, Lubomir M.; Chan, Heang-Ping; Sahiner, Berkman; Petrick, Nicholas; Helvie, Mark A.; Roubidoux, Marilyn A.; Gurcan, Metin N.

    2002-05-01

    We have previously demonstrated that interval change analysis can improve differentiation of malignant and benign masses. In this study, a new classification scheme using interval change information was developed to classify mammographic microcalcification clusters as malignant and benign. From each cluster, 20 run length statistic texture features (RLSF) and 21 morphological features were extracted. Twenty difference RLSF were obtained by subtracting a prior RLSF from the corresponding current RLSF. The feature space consisted of the current and the difference RLSF, as well as the current and the difference morphological features. A leave-one-case-out resampling was used to train and test the classifier using 65 temporal image pairs (19 malignant, 46 benign) containing biopsy-proven microcalcification clusters. Stepwise feature selection and a linear discriminant classifier, designed with the training subsets alone, were used to select and merge the most useful features. An average of 12 features were selected from the training subsets, of which 3 difference RLSF and 7 morphological features were consistently selected from most of the training subsets. The classifier achieved an average training Az of 0.98 and a test Az of 0.87. For comparison, a classifier based on the current single image features achieved an average training Az of 0.88 and test Az of 0.81. These results indicate that the use of temporal information improved the accuracy of microcalcification characterization.

  9. Screening for occult malignancy with FDG-PET/CT in patients with unprovoked venous thromboembolism.

    PubMed

    Alfonso, Ana; Redondo, Margarita; Rubio, Tomás; Del Olmo, Beatriz; Rodríguez-Wilhelmi, Pablo; García-Velloso, María J; Richter, José A; Páramo, José A; Lecumberri, Ramón

    2013-11-01

    Extensive screening strategies to detect occult cancer in patients with unprovoked venous thromboembolism (VTE) are complex and no benefit in terms of survival has been reported. FDG-PET/CT (2-[F-18] fluoro-2-deoxy-D-glucose positron emission tomography combined with computed tomography), a noninvasive technique for the diagnosis and staging of malignancies, could be useful in this setting. Consecutive patients ≥ 50 years with a first unprovoked VTE episode were prospectively included. Screening with FDG-PET/CT was performed 3-4 weeks after the index event. If positive, appropriate diagnostic work-up was programmed. Clinical follow-up continued for 2 years. Blood samples were collected to assess coagulation biomarkers. FDG-PET/CT was negative in 68/99 patients (68.7%), while suspicious FDG uptake was detected in 31/99 patients (31.3%). Additional diagnostic work-up confirmed a malignancy in 7/31 patients (22.6%), with six of them at early stage. During follow-up, two patients with negative FDG-PET/CT were diagnosed with cancer. Sensitivity (S), positive (PPV) and negative predictive values (NPV) of FDG-PET/CT as single tool for the detection of occult malignancy were 77.8% (95% CI: 0.51-1), 22.6% (95% CI: 0.08-0.37) and 97.1% (95% CI: 0.93-1), respectively. Median tissue factor (TF) activity in patients with occult cancer was 5.38 pM vs. 2.40 pM in those without cancer (p = 0.03). Limitation of FDG-PET/CT screening to patients with TF activity > 2.8 pM would improve the PPV to 37.5% and reduce the costs of a single cancer diagnosis from 20,711€ to 11,670€. FDG-PET/CT is feasible for the screening of occult cancer in patients with unprovoked VTE, showing high S and NPV. The addition of TF activity determination may be useful for patient selection. PMID:23616232

  10. Wavelet-Based 3D Reconstruction of Microcalcification Clusters from Two Mammographic Views: New Evidence That Fractal Tumors Are Malignant and Euclidean Tumors Are Benign

    PubMed Central

    Batchelder, Kendra A.; Tanenbaum, Aaron B.; Albert, Seth; Guimond, Lyne; Kestener, Pierre; Arneodo, Alain; Khalil, Andre

    2014-01-01

    The 2D Wavelet-Transform Modulus Maxima (WTMM) method was used to detect microcalcifications (MC) in human breast tissue seen in mammograms and to characterize the fractal geometry of benign and malignant MC clusters. This was done in the context of a preliminary analysis of a small dataset, via a novel way to partition the wavelet-transform space-scale skeleton. For the first time, the estimated 3D fractal structure of a breast lesion was inferred by pairing the information from two separate 2D projected mammographic views of the same breast, i.e. the cranial-caudal (CC) and mediolateral-oblique (MLO) views. As a novelty, we define the “CC-MLO fractal dimension plot”, where a “fractal zone” and “Euclidean zones” (non-fractal) are defined. 118 images (59 cases, 25 malignant and 34 benign) obtained from a digital databank of mammograms with known radiologist diagnostics were analyzed to determine which cases would be plotted in the fractal zone and which cases would fall in the Euclidean zones. 92% of malignant breast lesions studied (23 out of 25 cases) were in the fractal zone while 88% of the benign lesions were in the Euclidean zones (30 out of 34 cases). Furthermore, a Bayesian statistical analysis shows that, with 95% credibility, the probability that fractal breast lesions are malignant is between 74% and 98%. Alternatively, with 95% credibility, the probability that Euclidean breast lesions are benign is between 76% and 96%. These results support the notion that the fractal structure of malignant tumors is more likely to be associated with an invasive behavior into the surrounding tissue compared to the less invasive, Euclidean structure of benign tumors. Finally, based on indirect 3D reconstructions from the 2D views, we conjecture that all breast tumors considered in this study, benign and malignant, fractal or Euclidean, restrict their growth to 2-dimensional manifolds within the breast tissue. PMID:25222610

  11. Migrating Polyarthritis as a Feature of Occult Malignancy: 2 Case Reports and a Review of the Literature

    PubMed Central

    Watson, Geoffrey Alan; O'Neill, Lorraine; Law, Ruth; McCarthy, Geraldine; Veale, Douglas

    2015-01-01

    Malignant disease may be associated with a wide variety of musculoskeletal syndromes. Rarely the musculoskeletal system can be indirectly affected by paraneoplastic phenomena, such as carcinomatous polyarthritis (CP). The differential diagnosis for CP is broad and is often a diagnosis of exclusion. CP often presents similarly to other forms of inflammatory arthritis, and a detailed history and physical examination can often distinguish CP from other more common causes of polyarticular arthritis. However serological tests such as rheumatoid factor (RF) and anti-citrullinated peptide (anti-CCP) antibody positivity, while rare, can be misleading. Clinical awareness and suspicion are paramount in achieving an accurate diagnosis and early detection of an occult neoplasm is critical for prompt management and therapy. We report two cases presenting with this unique clinical phenotype associated with paraneoplastic polyarthropathy and review the literature. PMID:26558124

  12. Assessment of Breast Specimens With or Without Calcifications in Diagnosing Malignant and Atypia for Mammographic Breast Microcalcifications Without Mass

    PubMed Central

    Cheung, Yun-Chung; Juan, Yu-Hsiang; Ueng, Shir-Hwa; Lo, Yung-Feng; Huang, Pei-Chin; Lin, Yu-Ching; Chen, Shin-Cheh

    2015-01-01

    Abstract Presence of microcalcifications within the specimens frequently signifies a successful attempt of stereotactic vacuum-assisted breast biopsy (VABB) in obtaining a pathologic diagnosis of the breast microcalcifications. In this study, the authors aimed to assess and compare the accuracy and consistency of calcified or noncalcified specimens obtained from same sites of sampling on isolated microcalcifications without mass in diagnosing high-risk and malignant lesions. To the best of our knowledge, an individual case-based prospective comparison has not been reported. With the approval from institutional review board of our hospital (Chang Gung Memorial Hospital), the authors retrospectively reviewed all clinical cases of stereotactic VABBs on isolated breast microcalcifications without mass from our database. The authors included those having either surgery performed or had clinical follow-up of at least 3 years for analysis. All the obtained specimens with or without calcification were identified using specimen radiographs and separately submitted for pathologic evaluation. The concordance of diagnosis was assessed for both atypia and malignant lesions. A total of 390 stereotactic VABB procedures (1206 calcified and 1456 noncalcified specimens) were collected and reviewed. The consistent rates between calcified and noncalcified specimens were low for atypia and malignant microcalcifications (44.44% in flat epithelial atypia, 46.51% in atypical ductal hyperplasia, 55.73% in ductal carcinoma in situ, and 71.42% in invasive ductal carcinoma). The discordance in VABB diagnoses indicated that 41.33% of malignant lesions would be misdiagnosed by noncalcified specimens. Furthermore, calcified specimens showed higher diagnostic accuracy of breast cancer as compared with the noncalcified specimens (91.54 % versus 69.49%, respectively). The evaluation of both noncalcified specimens and calcified specimens did not show improvement of diagnostic accuracy as compared

  13. Malignant hypertensive retinopathy as a presenting sign of an occult dead fetus

    PubMed Central

    Araújo, Joana; Tavares-Ferreira, João; Penas, Susana; Figueira, Luís; Paiva, Flávio Prézia; Falcão-Reis, Fernando

    2015-01-01

    We report one case of malignant hypertensive retinopathy as a presenting sign of fetal death in utero. Ophthalmic examination (including intravenous fluorescein angiography and optical coherence tomography) and obstetric and systemic evaluation were performed, providing a multidisciplinary approach. A 33-year-old overweight woman (body mass index 47 kg/m2) with no systemic or ocular known disease was admitted to our emergency department with a one-week history of bilateral vision loss and no systemic complaints. On examination, best corrected visual acuity was 1/10 in the right eye and 1/10 in the left eye. Anterior segment examination of both eyes was unremarkable. Ophthalmoscopic fundus findings included bilateral optic disc edema, diffuse cotton wool spots, intraretinal exudates, retinal hemorrhages, and multiple serous retinal detachments involving both maculae. Physical examination revealed a blood pressure of 220/110 mmHg. Further systemic workup revealed a previously unknown 35-week pregnancy with a dead fetus. An emergency cesarean section was performed. Pre-eclampsia is a life-threatening disorder for both mother and fetus. This case highlights the need to rule out pre-eclampsia in all women of childbearing age presenting with ocular signs of malignant hypertension, even without external signs of pregnancy. PMID:26082609

  14. Assessment of Breast Specimens With or Without Calcifications in Diagnosing Malignant and Atypia for Mammographic Breast Microcalcifications Without Mass: A STARD-Compliant Diagnostic Accuracy Article.

    PubMed

    Cheung, Yun-Chung; Juan, Yu-Hsiang; Ueng, Shir-Hwa; Lo, Yung-Feng; Huang, Pei-Chin; Lin, Yu-Ching; Chen, Shin-Cheh

    2015-10-01

    Presence of microcalcifications within the specimens frequently signifies a successful attempt of stereotactic vacuum-assisted breast biopsy (VABB) in obtaining a pathologic diagnosis of the breast microcalcifications. In this study, the authors aimed to assess and compare the accuracy and consistency of calcified or noncalcified specimens obtained from same sites of sampling on isolated microcalcifications without mass in diagnosing high-risk and malignant lesions. To the best of our knowledge, an individual case-based prospective comparison has not been reported.With the approval from institutional review board of our hospital (Chang Gung Memorial Hospital), the authors retrospectively reviewed all clinical cases of stereotactic VABBs on isolated breast microcalcifications without mass from our database. The authors included those having either surgery performed or had clinical follow-up of at least 3 years for analysis. All the obtained specimens with or without calcification were identified using specimen radiographs and separately submitted for pathologic evaluation. The concordance of diagnosis was assessed for both atypia and malignant lesions.A total of 390 stereotactic VABB procedures (1206 calcified and 1456 noncalcified specimens) were collected and reviewed. The consistent rates between calcified and noncalcified specimens were low for atypia and malignant microcalcifications (44.44% in flat epithelial atypia, 46.51% in atypical ductal hyperplasia, 55.73% in ductal carcinoma in situ, and 71.42% in invasive ductal carcinoma). The discordance in VABB diagnoses indicated that 41.33% of malignant lesions would be misdiagnosed by noncalcified specimens. Furthermore, calcified specimens showed higher diagnostic accuracy of breast cancer as compared with the noncalcified specimens (91.54 % versus 69.49%, respectively). The evaluation of both noncalcified specimens and calcified specimens did not show improvement of diagnostic accuracy as compared with

  15. Tumor location and detectability in mammographic screening

    SciTech Connect

    Schmitt, E.L.; Threatt, B.

    1982-10-01

    The adequacy of a film mammogram that does not visualize the retromammary space or ribs has concerned radiologists. The 79 prevalent cancers detected in the 10,000 self-referred woman at the University of Michigan Breast Cancer Detection Demonstration Project were analyzed for number of films required to detect the cancer, relationship of the cancer to the posterior edge of the film, number of occult lesions, tumor size, histologic type, sensitivity of detection method, and number of interval carcinomas. The mammograms were obtained using a dedicated mammographic machine and the upright position, with visualization of the anterior axillary fold on the mediolateral view. The ribs were not imaged. Of the 79 cancers, 76 were detectable on the mammogram. All were visualized on the mediolateral view, while three were not imaged on the craniocaudal view. Twelve percent of the cancers were within 1 cm of the posterior edge of the film. Only six ''interval'' carcinomas were found in the 10,000 patients within the year of the initial examinations; these women had dense P2 or DY mammographic parenchymal patterns. The detected cancers were smaller and had a significantly higher percentage of noninvasive cancers than in a symptomatic clinical population. Thus, properly exposed film mammograms using vigorous breast compression examine the breast adequately without visualizing the ribs.

  16. Vitamin D and Mammographic Findings

    PubMed Central

    Riedel, J.; Straub, L.; Wissing, J.; Artmann, A.; Schmidmayr, M.; Kiechle, M.; Seifert-Klauss, V. R.

    2016-01-01

    Introduction: Pleiotropic immune-modulatory and anti-proliferative effects of vitamin D and hopes to stop cancerogenesis have led to an increased interest in possible reduction of breast cancer with higher vitamin D levels. Mammographic density is an established risk factor for breast cancer risk, and its association with serum vitamin D is complex, as recent studies have shown. Patients and Methods: In this cross-sectional study, 1103 participants were recruited in the breast diagnostic unit of the Klinikum rechts der Isar, TU Munich. A standardised questionnaire and blood samples for 25-OH-vitamin D were taken on the day of mammography. Histologic results of biopsies in suspicious mammographies were documented. Results: In the 1090 data-sets analysed, vitamin D-deficiency was common among women under 40. Highest vitamin D values were observed in participants aged 60–69 years, but average values for all age cohorts were below 20 ng/ml of vitamin D. 15.6 % of all participants had very low vitamin D values (< 10 ng/ml), 51.3 % were vitamin D-deficient (10–19 ng/ml) and only 5.7 % were above 30 ng/ml, i.e. showed sufficient vitamin D. Patients with malignant results had vitamin D < 10 ng/ml more often (16.9 %; p = 0.61), and only 3.4 % in this group had sufficient vitamin D supply (> 30 ng/ml). There were no significant differences in vitamin D-levels between density groups according to the American College of Radiology (ACR) criteria. Conclusion: Vitamin D values were lower than in comparable US women. Up to now, there is no direct clinical evidence for a relationship between the risk for breast cancer and a specific vitamin D value. PMID:27239067

  17. Computed tomography guided localization of clinically occult breast carcinoma-the ''N'' skin guide

    SciTech Connect

    Kopans, D.B.; Meyer, J.E.

    1982-10-01

    Standard computed tomography (CT) can be used for the three-dimensional localization of clinically occult suspicious breast lesions whose exact position cannot be determined by standard mammographic views. A method is described that facilitates accurate preoperative needle localization using CT guidance, once the position of these lesions is defined.

  18. The occult urothelial cancer.

    PubMed

    Ragonese, Mauro; Racioppi, Marco; D'Agostino, Daniele; Di Gianfrancesco, Luca; Lenci, Niccolò; Bientinesi, Riccardo; Palermo, Giuseppe; Sacco, Emilio; Pinto, Francesco; Bassi, Pier Francesco

    2016-05-24

    Transitional cell carcinoma (TCC) is the tumor that most frequently affects the urinary tract. The most common location is in the bladder; the diagnosis, as the follow-up, is based on urine cytology, endoscopic, and radiological examinations. Urinary cytology is an important non invasive tool used in the diagnosis and follow-up of patients with TCC. A positive urine cytology result is highly predictive of the presence of TCC, even in the presence of normal cystoscopy, because malignant cells may appear in the urine long time before any cystoscopically visible lesion becomes apparent. The presence of a positive urinary cytology, in the absence of clinical or endoscopic evidence of a TCC, can identify an occult urothelial cancer, located in any site of the urinary tract (upper urinary tract, bladder, prostatic urethra). Most of the urothelial tumors of the renal pelvis and ureters are diagnosed by radiological examinations, but we can observe a high rate of false negatives. In order to improve the diagnostic role of urinary cytology and other conventional examinations, numerous molecular markers have been identified; however, the real clinical application remains unclear. Photodynamic diagnosis and narrow band imaging (NBI) cystoscopy increase the diagnostic accuracy of endoscopic examinations in the presence of lesions not easily detectable. The aim of this review is to analyze the current diagnostic standards in the presence of occult urothelial cancer.

  19. Malignant hyperechoic breast lesions at ultrasound: A pictorial essay.

    PubMed

    Tiang, Stephen; Metcalf, Cecily; Dissanayake, Deepthi; Wylie, Elizabeth

    2016-08-01

    Malignant breast lesions are typically hypoechoic at sonography. However, a small subgroup of hyperechoic malignant breast lesions is encountered in clinical practice. We present a pictorial essay of a number of different hyperechoic breast malignancies with mammographic, sonographic and histopathologic correlation. Suspicious sonographic features in a hyperechoic lesion include inhomogeneity in echogenic pattern, an irregular margin, posterior acoustic shadowing and internal vascularity. A hyperechoic lesion at ultrasound does not discount the need to undertake histological assessment of a mammographically suspicious lesion.

  20. Screening for occult lung cancer.

    PubMed Central

    Barclay, T. H.; MacIntosh, J. H.

    1983-01-01

    A pilot screening program for the early detection of lung cancer was carried out in Saskatchewan in 1968 using chest roentgenography and cytologic examination of sputum samples. The yield from 23 000 men aged 40 years and over was only 10 cases. Nine of the men had advanced disease. One had occult lung cancer. A period of 31 months elapsed between the discovery of malignant cells in this patient's sputum and roentgenographic localization of the tumour. Following pneumonectomy he has survived with no discernible residual or metastatic tumour for 12 years. The morphologic changes in the resected lung provided a basis for discussing the preclinical phase of squamous cancer of the lung, the treatment of occult cancer and multicentric primary pulmonary tumours. The survey would have been more successful with a narrower target group and more frequent examination. Images FIG. 1 FIG. 2 FIG. 3 PMID:6299495

  1. Radioimmune localization of occult carcinoma

    SciTech Connect

    Duda, R.B.; Zimmer, A.M.; Rosen, S.T.; Gilyon, K.A.; Webber, D.; Spies, S.; Spies, W.; Merchant, B. )

    1990-07-01

    Patients with a rising serum carcinoembryonic antigen level and no clinical or roentgenographic evidence of recurrent or metastatic cancer present a treatment dilemma. Eleven such patients, 10 with a previously treated colorectal carcinoma and 1 with a previously treated breast carcinoma, received an injection of the anticarcinoembryonic antigen monoclonal antibody ZCE-025 labeled with the radioisotope indium 111. Nuclear scintigraphy was performed on days 3 and 5 through 7 to detect potential sites of tumor recurrence. The monoclonal antibody scan accurately predicted the presence or absence of occult malignancy in 7 (64%) patients. Second-look laparotomy confirmed the monoclonal antibody scan results in the patients with colorectal cancer, and magnetic resonance imaging confirmed metastatic breast cancer. This study demonstrates that In-ZCE-025 can localize occult carcinoma and may assist the surgeon in facilitating the operative exploration. In-ZCE-025 assisted in the initiation of adjuvant therapy for the patient with breast cancer.

  2. The impact of mammographic density and lesion location on detection

    NASA Astrophysics Data System (ADS)

    Al Mousa, Dana; Ryan, Elaine; Lee, Warwick; Nickson, Carolyn; Pietrzyk, Mariusz; Reed, Warren; Poulos, Ann; Li, Yanpeng; Brennan, Patrick

    2013-03-01

    The aim of this study is to examine the impact of breast density and lesion location on detection. A set of 55 mammographic images (23 abnormal images with 26 lesions and 32 normal images) were examined by 22 expert radiologists. The images were classified by an expert radiologist according to the Synoptic Breast Imaging Report of the National Breast Cancer Centre (NBCC) as having low mammographic density (D1<25% glandular and D2> 25-50% glandular) or high density (D3 51-75% glandular and D4> 75-glandular). The observers freely examined the images and located any malignancy using a 5-point confidence. Performance was defined using the following metrics: sensitivity, location sensitivity, specificity, receiver operating characteristic (ROC Az) curves and jackknife free-response receiver operator characteristics (JAFROC) figures of merit. Significant increases in sensitivity (p= 0.0174) and ROC (p=0.0001) values were noted for the higher density compared with lower density images according to NBCC classification. No differences were seen in radiologists' performance between lesions within or outside the fibroglandular region. In conclusion, analysis of our data suggests that radiologists scored higher using traditional metrics in higher mammographic density images without any improvement in lesion localisation. Lesion location whether within or outside the fibroglandular region appeared to have no impact on detection abilities suggesting that if a masking effect is present the impact is minimal. Eye-tracking analyses are ongoing.

  3. Improved mammographic interpretation of masses using computer-aided diagnosis.

    PubMed

    Leichter, I; Fields, S; Nirel, R; Bamberger, P; Novak, B; Lederman, R; Buchbinder, S

    2000-01-01

    The aim of this study was to evaluate the effectiveness of computerized image enhancement, to investigate criteria for discriminating benign from malignant mammographic findings by computer-aided diagnosis (CAD), and to test the role of quantitative analysis in improving the accuracy of interpretation of mass lesions. Forty sequential mammographically detected mass lesions referred for biopsy were digitized at high resolution for computerized evaluation. A prototype CAD system which included image enhancement algorithms was used for a better visualization of the lesions. Quantitative features which characterize the spiculation were automatically extracted by the CAD system for a user-defined region of interest (ROI). Reference ranges for malignant and benign cases were acquired from data generated by 214 known retrospective cases. The extracted parameters together with the reference ranges were presented to the radiologist for the analysis of 40 prospective cases. A pattern recognition scheme based on discriminant analysis was trained on the 214 retrospective cases, and applied to the prospective cases. Accuracy of interpretation with and without the CAD system, as well as the performance of the pattern recognition scheme, were analyzed using receiver operating characteristics (ROC) curves. A significant difference (p < 0.005) was found between features extracted by the CAD system for benign and malignant cases. Specificity of the CAD-assisted diagnosis improved significantly (p < 0.02) from 14 % for the conventional assessment to 50 %, and the positive predictive value increased from 0.47 to 0.62 (p < 0.04). The area under the ROC curve (A(z)) increased significantly (p < 0. 001) from 0.66 for the conventional assessment to 0.81 for the CAD-assisted analysis. The A(z) for the results of the pattern recognition scheme was higher (0.95). The results indicate that there is an improved accuracy of diagnosis with the use of the mammographic CAD system above that of the

  4. The Occult Today: Why?

    ERIC Educational Resources Information Center

    Kessler, Gary E.

    1975-01-01

    Author offered some reflections on the "why" of the contemporary interest in the occult. He attempted to convince the reader that, if he or she has been surprised by the recent rise of occultism, sober reflection will dispell some fears and, perhaps, even convince him or her that occultism is not merely superstition. (Author/RK)

  5. Risk of Occult Uterine Sarcoma in Presumed Uterine Fibroids.

    PubMed

    Cui, Rosa R; Wright, Jason D

    2016-03-01

    Symptomatic fibroids are a common indication for hysterectomy or myomectomy. Although rare, unexpected gynecologic malignancies in presumed fibroids have been documented. In cases where tissue retrieval is performed through morcellation, there is increasing concern that intra-abdominal dispersion of occult uterine malignancies may lead to peritoneal dissemination and worse outcomes. We examined the available literature to determine the prevalence of all uterine cancers in women undergoing hysterectomy or myomectomy for benign uterine disease, with attention to the risk of morcellating occult uterine sarcomas. We also reviewed the available tools for preoperative discrimination between benign and malignant uterine disease. PMID:26645385

  6. Deep shadow occulter

    NASA Technical Reports Server (NTRS)

    Cash, Webster (Inventor)

    2010-01-01

    Methods and apparatus are disclosed for occulting light. The occulter shape suppresses diffraction at any given size or angle and is practical to build because it can be made binary to avoid scatter. Binary structures may be fully opaque or fully transmitting at specific points. The diffraction suppression is spectrally broad so that it may be used with incoherent white light. An occulter may also include substantially opaque inner portion and an at least partially transparent outer portion. Such occulters may be used on the ground to create a deep shadow in a short distance, or may be used in space to suppress starlight and reveal exoplanets.

  7. Mammographic quantitative image analysis and biologic image composition for breast lesion characterization and classification

    SciTech Connect

    Drukker, Karen Giger, Maryellen L.; Li, Hui; Duewer, Fred; Malkov, Serghei; Joe, Bonnie; Kerlikowske, Karla; Shepherd, John A.; Flowers, Chris I.; Drukteinis, Jennifer S.

    2014-03-15

    Purpose: To investigate whether biologic image composition of mammographic lesions can improve upon existing mammographic quantitative image analysis (QIA) in estimating the probability of malignancy. Methods: The study population consisted of 45 breast lesions imaged with dual-energy mammography prior to breast biopsy with final diagnosis resulting in 10 invasive ductal carcinomas, 5 ductal carcinomain situ, 11 fibroadenomas, and 19 other benign diagnoses. Analysis was threefold: (1) The raw low-energy mammographic images were analyzed with an established in-house QIA method, “QIA alone,” (2) the three-compartment breast (3CB) composition measure—derived from the dual-energy mammography—of water, lipid, and protein thickness were assessed, “3CB alone”, and (3) information from QIA and 3CB was combined, “QIA + 3CB.” Analysis was initiated from radiologist-indicated lesion centers and was otherwise fully automated. Steps of the QIA and 3CB methods were lesion segmentation, characterization, and subsequent classification for malignancy in leave-one-case-out cross-validation. Performance assessment included box plots, Bland–Altman plots, and Receiver Operating Characteristic (ROC) analysis. Results: The area under the ROC curve (AUC) for distinguishing between benign and malignant lesions (invasive and DCIS) was 0.81 (standard error 0.07) for the “QIA alone” method, 0.72 (0.07) for “3CB alone” method, and 0.86 (0.04) for “QIA+3CB” combined. The difference in AUC was 0.043 between “QIA + 3CB” and “QIA alone” but failed to reach statistical significance (95% confidence interval [–0.17 to + 0.26]). Conclusions: In this pilot study analyzing the new 3CB imaging modality, knowledge of the composition of breast lesions and their periphery appeared additive in combination with existing mammographic QIA methods for the distinction between different benign and malignant lesion types.

  8. CADx of mammographic masses and clustered microcalcifications: A review

    SciTech Connect

    Elter, Matthias; Horsch, Alexander

    2009-06-15

    Breast cancer is the most common type of cancer among women in the western world. While mammography is regarded as the most effective tool for the detection and diagnosis of breast cancer, the interpretation of mammograms is a difficult and error-prone task. Hence, computer aids have been developed that assist the radiologist in the interpretation of mammograms. Computer-aided detection (CADe) systems address the problem that radiologists often miss signs of cancers that are retrospectively visible in mammograms. Furthermore, computer-aided diagnosis (CADx) systems have been proposed that assist the radiologist in the classification of mammographic lesions as benign or malignant. While a broad variety of approaches to both CADe and CADx systems have been published in the past two decades, an extensive survey of the state of the art is only available for CADe approaches. Therefore, a comprehensive review of the state of the art of CADx approaches is presented in this work. Besides providing a summary, the goals for this article are to identify relations, contradictions, and gaps in literature, and to suggest directions for future research. Because of the vast amount of publications on the topic, this survey is restricted to the two most important types of mammographic lesions: masses and clustered microcalcifications. Furthermore, it focuses on articles published in international journals.

  9. An Occult Malignancy Behind a Demyelinating Disease

    PubMed Central

    Lo Presti, Saberio; Kanagarajah, Prashanth; Pirela, Daniela; Morlote, Diana; Cusnir, Mike

    2016-01-01

    We report a case of a 38-year-old man presenting with bilateral lower extremity weakness and paresthesias that progressed during a 4-month period to severe polyneuropathy forcing the patient to be bed bound. Throughout his multiple hospitalizations, he was treated erroneously for chronic inflammatory demyelinating polyneuropathy, without significant improvement in his symptoms. In addition, he developed hepatosplenomegaly (organomegaly); endocrinopathies such as diabetes mellitus, central hypogonadism, and hypothyroidism; monoclonal spike evidenced in the serum electrophoresis; and hyperpigmentation of skin, altogether consistent with POEMS syndrome. During his last hospitalization he developed excruciating pain on his left hip, and imaging revealed the presence of a 9 × 6 cm osteolytic mass with sclerotic rim in the left acetabulum. Biopsy of the mass confirmed an isolated IgG lambda plasmacytoma. The patient received radiation to his left acetabular lesion followed by left hip replacement. Subsequently, the patient underwent autologous bone marrow transplant. Eighteen months after his initial presentation, he had satisfactory clinical response and is functional without significant limitations. POEMS syndrome is a rare paraneoplastic syndrome secondary to an underlying plasma cell disorder, which can oftentimes be overlooked and misdiagnosed. The median age of presentation is 51 years, and only 31% of the cases occur in fairly young patients under the age of 45 as evidenced in this case. As clinicians, we should be aware of the constellation of features associated with POEMS syndrome and be able to recognize them promptly. PMID:27790622

  10. Occulter Starshade Technology Development

    NASA Astrophysics Data System (ADS)

    Lisman, P. D.; Thomson, M.; Kissil, A.; Walkemeyer, P.; Polanco, O.

    2010-10-01

    Imaging Earth-like exoplanets with a free flying occulter requires developing a large, lightweight, flower-shaped, deployable structure with precisely controlled edge position and profile. In-plane tolerance requirements are considerably tighter than heritage antenna systems, but the more difficult to control out-of-plane tolerances are actually much looser. This paper presents a novel occulter mechanical design that delivers the required performance with a highly reliable deployment scheme. A very compact stowed volume is an added benefit that enables launching the occulter together with a 1 to 2m class telescope, using a single, currently available launch vehicle. Demonstrating the petal deployment function and compliance with key tolerance specifications is the focus of current technology efforts. A series of prototype models of increasing fidelity are planned, starting with a proof of concept model that is currently in fabrication. The occulter design and current development status is presented herein.

  11. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Mammographic x-ray system. 892.1710 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system. (a) Identification. A mammographic x-ray system is a device intended to be used to produce radiographs of the...

  12. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Mammographic x-ray system. 892.1710 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system. (a) Identification. A mammographic x-ray system is a device intended to be used to produce radiographs of the...

  13. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Mammographic x-ray system. 892.1710 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system. (a) Identification. A mammographic x-ray system is a device intended to be used to produce radiographs of the...

  14. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Mammographic x-ray system. 892.1710 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system. (a) Identification. A mammographic x-ray system is a device intended to be used to produce radiographs of the...

  15. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mammographic x-ray system. 892.1710 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system. (a) Identification. A mammographic x-ray system is a device intended to be used to produce radiographs of the...

  16. Artificial-neural-network-based classification of mammographic microcalcifications using image structure features

    NASA Astrophysics Data System (ADS)

    Dhawan, Atam P.; Chitre, Yateen S.; Moskowitz, Myron

    1993-07-01

    Mammography associated with clinical breast examination and self-breast examination is the only effective and viable method for mass breast screening. It is however, difficult to distinguish between benign and malignant microcalcifications associated with breast cancer. Most of the techniques used in the computerized analysis of mammographic microcalcifications segment the digitized gray-level image into regions representing microcalcifications. We present a second-order gray-level histogram based feature extraction approach to extract microcalcification features. These features, called image structure features, are computed from the second-order gray-level histogram statistics, and do not require segmentation of the original image into binary regions. Several image structure features were computed for 100 cases of `difficult to diagnose' microcalcification cases with known biopsy results. These features were analyzed in a correlation study which provided a set of five best image structure features. A feedforward backpropagation neural network was used to classify mammographic microcalcifications using the image structure features. The network was trained on 10 cases of mammographic microcalcifications and tested on additional 85 `difficult-to-diagnose' microcalcifications cases using the selected image structure features. The trained network yielded good results for classification of `difficult-to- diagnose' microcalcifications into benign and malignant categories.

  17. Mammographic screening: measurement of the cost in a population based programme in Victoria, Australia.

    PubMed Central

    Hurley, S F; Livingston, P M; Thane, N; Quang, L

    1994-01-01

    STUDY OBJECTIVES--To estimate the cost per woman participating in a mammographic screening programme, and to describe methods for measuring costs. DESIGN--Expenditure, resource usage, and throughput were monitored over a 12 month period. Unit costs for each phase of the screening process were estimated and linked with the probabilities of each screening outcome to obtain the cost per woman screened and the cost per breast cancer detected. SETTING--A pilot, population based Australian programme offering free two-view mammographic screening. PARTICIPANTS--A total of 5986 women aged 50-69 years who lived in the target area, were listed on the electoral roll, had no previous breast cancer, and attended the programme. RESULTS--Unit costs for recruitment, screening, and recall mammography were $17.54, $60.04, and $175.54, respectively. The costs of clinical assessment for women with subsequent clear, benign, malignant (palpable), and malignant (impalpable) diagnoses were $173.71, $527.29, $436.62, and $567.22, respectively. The cost per woman screened was $117.70, and the cost per breast cancer detected was $11,550. CONCLUSIONS--The cost per woman screened is a key variable in assessment of the cost effectiveness of mammographic screening, and is likely to vary between health care settings. Its measurement is justified if decisions about health care services are to be based on cost effectiveness criteria. PMID:7964340

  18. Occult breast tumor reservoir: biological properties and clinical significance.

    PubMed

    Santen, Richard J; Yue, Wei; Heitjan, Daniel F

    2013-08-01

    Small, occult, undiagnosed breast cancers are found at autopsy in up to 15.6 % of women dying from unrelated causes with an average of 7 % from eight separate studies. The mammographic detection threshold of breast tumors ranges from 0.88 to 1.66 cm in diameter based on the patient's age. Tumor growth rates, expressed as "effective doubling times," vary from 10 to >700 days. We previously reported two models, based on iterative analysis of these parameters, to describe the biologic behavior of undiagnosed, occult breast tumors. Our models facilitate interpretation of the Women's Health Initiative (WHI) and antiestrogen breast cancer prevention studies. A nude mouse xenograft model was used to validate our assumption that breast tumors grow in a log-linear fashion. We then used our previously reported occult tumor growth (OTG) and computer-simulated tumor growth models to analyze various clinical trial data. Parameters used in the OTG model included a 200-day effective doubling time, 7 % prevalence of occult tumors, and 1.16 cm detection threshold. These models had been validated by comparing predicted with observed incidence of breast cancer in eight different populations of women. Our model suggests that menopausal hormone therapy with estrogens plus a progestogen (E + P) in the WHI trial primarily promoted the growth of pre-existing, occult lesions and minimally initiated de novo tumors. We provide a potential explanation for the lack of an increase in breast cancer incidence in the subgroup of women in the WHI who had not received E + P prior to randomization. This result may have reflected a leftward skew in the distribution of occult tumor doublings and insufficient time for stimulated tumors to reach the detection threshold. Our model predicted that estrogen alone reduced the incidence of breast cancer as a result of apoptosis. Understanding of the biology of occult tumors suggests that breast cancer "prevention" with antiestrogens or aromatase

  19. Improving Performance of Computer-Aided Detection of Masses by Incorporating Bilateral Mammographic Density Asymmetry: An Assessment

    PubMed Central

    Wang, Xingwei; Li, Lihua; Xu, Weidong; Liu, Wei; Lederman, Dror; Zheng, Bin

    2011-01-01

    Rationale and Objectives Bilateral mammographic density asymmetry is a promising indicator in assessing risk of having or developing breast cancer. This study aims to assess the performance improvement of a computer-aided detection (CAD) scheme in detecting masses by incorporating bilateral mammographic density asymmetrical information. Materials and Methods A testing dataset containing 2400 full-field digital mammograms (FFDM) acquired from 600 examination cases was established. Among them, 300 are positive cases with verified cancer associated with malignant masses and 300 are negative cases. Two computerized schemes were applied to process images of each case. The first single-image based CAD scheme detected suspicious mass regions and the second scheme computed average and difference of mammographic tissue density depicted between the left and right breast. A fusion method based on rotation of the CAD scoring projection reference axis was then applied to combine CAD-generated mass detection scores and either the computed average or difference (asymmetry) of bilateral mammographic density scores. The CAD performance levels with and without incorporating mammographic density information were evaluated and compared using a free-response receiver operating characteristic (FROC) type data analysis method. Results CAD achieved a case-based mass detection sensitivity of 0.74 and a region-based sensitivity of 0.56 at a false-positive rate of 0.25 per image. By fusing the CAD and bilateral mammographic density asymmetry scores, the case-based and region-based sensitivity levels of the CAD scheme were increased to 0.84 and 0.69, respectively, at the same false-positive rate. Fusion with average mammographic density only slightly increased CAD sensitivity to 0.75 (case-based) and 0.57 (region-based). Conclusions This study indicated that (1) bilateral mammographic density asymmetry was a stronger indicator of the case depicting suspicious masses than the average density

  20. Role of computer-assisted visual search in mammographic interpretation

    NASA Astrophysics Data System (ADS)

    Nodine, Calvin F.; Kundel, Harold L.; Mello-Thoms, Claudia; Weinstein, Susan P.

    2001-06-01

    We used eye-position data to develop Computer-Assisted Visual Search (CAVS) as an aid to mammographic interpretation. CAVS feeds back regions of interest that receive prolonged visual dwell (greater than or equal to 1000 ms) by highlighting them on the mammogram. These regions are then reevaluated for possible missed breast cancers. Six radiology residents and fellows interpreted a test set of 40 mammograms twice, once with CAVS feedback (FB), and once without CAVS FB in a crossover, repeated- measures design. Eye position was monitored. LROC performance (area) was compared with and without CAVS FB. Detection and localization of malignant lesions improved 12% with CAVS FB. This was not significant. The test set contained subtle malignant lesions. 65% (176/272) of true lesions were fixated. Of those fixated, 49% (87/176) received prolonged attention resulting in CAVS FB, and 54% (47/87) of FBs resulted in TPs. Test-set difficulty and the lack of reading experience of the readers may have contributed to the relatively low overall performance, and may have also limited the effectiveness of CAVS FB which could only play a role in localizing potential lesions if the reader fixated and dwelled on them.

  1. Venous thromboembolism and occult cancer: impact on clinical practice.

    PubMed

    Gheshmy, Afshan; Carrier, Marc

    2016-04-01

    Unprovoked venous thromboembolism (VTE) can be the first manifestation of cancer. Given this relationship between unprovoked VTE and cancer, it is appealing for clinicians to screen their patients with a first episode of acute unprovoked VTE for a potential occult malignancy. Five different studies have compared a limited (thorough history and physical exam, basic bloodwork) to a more extensive occult cancer screening strategy (e.g. computed tomography, fludeoxyglucose positron emission tomography, etc.). Most of these studies have failed to show that an extensive occult cancer screening strategy diagnoses more occult cancer (including early cancers), misses fewer cancers during follow-up or improves overall and/or cancer-related mortality suggesting that extensive occult cancer screening should not be performed routinely. Therefore, patients with a first unprovoked VTE should undergo a limited cancer screening only and clinicians should ensure that their patients are up to date regarding age- and gender- specific cancer screening (colon, breast, cervix and prostate) as per their national recommendations. Current evidence does not support a net clinical benefit to perform an extensive occult cancer screening on all patients, and a decision to do additional testing should be made on a case by case basis.

  2. Venous thromboembolism and occult cancer: impact on clinical practice.

    PubMed

    Gheshmy, Afshan; Carrier, Marc

    2016-04-01

    Unprovoked venous thromboembolism (VTE) can be the first manifestation of cancer. Given this relationship between unprovoked VTE and cancer, it is appealing for clinicians to screen their patients with a first episode of acute unprovoked VTE for a potential occult malignancy. Five different studies have compared a limited (thorough history and physical exam, basic bloodwork) to a more extensive occult cancer screening strategy (e.g. computed tomography, fludeoxyglucose positron emission tomography, etc.). Most of these studies have failed to show that an extensive occult cancer screening strategy diagnoses more occult cancer (including early cancers), misses fewer cancers during follow-up or improves overall and/or cancer-related mortality suggesting that extensive occult cancer screening should not be performed routinely. Therefore, patients with a first unprovoked VTE should undergo a limited cancer screening only and clinicians should ensure that their patients are up to date regarding age- and gender- specific cancer screening (colon, breast, cervix and prostate) as per their national recommendations. Current evidence does not support a net clinical benefit to perform an extensive occult cancer screening on all patients, and a decision to do additional testing should be made on a case by case basis. PMID:27067984

  3. Association of mammographic image feature change and an increasing risk trend of developing breast cancer: an assessment

    NASA Astrophysics Data System (ADS)

    Tan, Maxine; Leader, Joseph K.; Liu, Hong; Zheng, Bin

    2015-03-01

    We recently investigated a new mammographic image feature based risk factor to predict near-term breast cancer risk after a woman has a negative mammographic screening. We hypothesized that unlike the conventional epidemiology-based long-term (or lifetime) risk factors, the mammographic image feature based risk factor value will increase as the time lag between the negative and positive mammography screening decreases. The purpose of this study is to test this hypothesis. From a large and diverse full-field digital mammography (FFDM) image database with 1278 cases, we collected all available sequential FFDM examinations for each case including the "current" and 1 to 3 most recently "prior" examinations. All "prior" examinations were interpreted negative, and "current" ones were either malignant or recalled negative/benign. We computed 92 global mammographic texture and density based features, and included three clinical risk factors (woman's age, family history and subjective breast density BIRADS ratings). On this initial feature set, we applied a fast and accurate Sequential Forward Floating Selection (SFFS) feature selection algorithm to reduce feature dimensionality. The features computed on both mammographic views were individually/ separately trained using two artificial neural network (ANN) classifiers. The classification scores of the two ANNs were then merged with a sequential ANN. The results show that the maximum adjusted odds ratios were 5.59, 7.98, and 15.77 for using the 3rd, 2nd, and 1st "prior" FFDM examinations, respectively, which demonstrates a higher association of mammographic image feature change and an increasing risk trend of developing breast cancer in the near-term after a negative screening.

  4. All about Occultation.

    ERIC Educational Resources Information Center

    Riddle, Bob

    2001-01-01

    Describes occultation events involving the moon, when the moon blocks the view of planets or stars. Describes other events such as a partial solar eclipse, a penumbral lunar eclipse, meteor showers, and moon phases. Provides a list of internet resources related to these events. (DLH)

  5. A GaAs pixel detectors-based digital mammographic system: Performances and imaging tests results

    NASA Astrophysics Data System (ADS)

    Annovazzi, A.; Amendolia, S. R.; Bigongiari, A.; Bisogni, M. G.; Catarsi, F.; Cesqui, F.; Cetronio, A.; Colombo, F.; Delogu, P.; Fantacci, M. E.; Gilberti, A.; Lanzieri, C.; Lavagna, S.; Novelli, M.; Passuello, G.; Paternoster, G.; Pieracci, M.; Poletti, M.; Quattrocchi, M.; Rosso, V.; Stefanini, A.; Testa, A.; Venturelli, L.

    2007-06-01

    The prototype presented in this paper is based on GaAs pixel detectors read-out by the PCC/MEDIPIX I circuit. The active area of a sensor is about 1 cm 2 therefore to cover the typical irradiation field used in mammography (18×24 cm 2), 18 GaAs detection units have been organized in two staggered rows of nine chips each and moved by a stepper motor in the orthogonal direction. The system is integrated in a mammographic equipment which comprehends the X-ray tube, the bias and data acquisition systems and the PC-based control system. The prototype has been developed in the framework of the Integrated Mammographic Imaging (IMI) project, an industrial research activity aiming to develop innovative instrumentation for morphologic and functional imaging. The project has been supported by the Italian Ministry of Education, University and Research (MIUR) and by five Italian High Tech companies, Alenia Marconi Systems (AMS), CAEN, Gilardoni, LABEN and Poli.Hi.Tech., in collaboration with the universities of Ferrara, Roma "La Sapienza", Pisa and the Istituto Nazionale di Fisica Nucleare (INFN). In this paper, we report on the electrical characterization and the first imaging test results of the digital mammographic system. To assess the imaging capability of such a detector we have built a phantom, which simulates the breast tissue with malignancies. The radiographs of the phantom, obtained by delivering an entrance dose of 4.8 mGy, have shown particulars with a measured contrast below 1%.

  6. Cancer-associated rheumatic disorders: clues to occult neoplasia.

    PubMed

    Nashitz, J E; Rosner, I; Rozenbaum, M; Elias, N; Yeshurun, D

    1995-02-01

    Interest in the rheumatologic manifestations of cancer is related in part to practical considerations, ie, earlier cancer diagnosis is possible through enhanced awareness of cancer-associated rheumatic syndromes. The spectrum of rheumatic disorders associated with cancer includes over 30 conditions, including hypertrophic osteoarthropathy, polymyalgia rheumatica, palmar fasciitis with polyarthritis, most autoimmune connective tissue diseases, and the more recently described antiphospholipid syndrome. It is generally held that extensive search for occult malignancy in most rheumatologic disorders is not cost efficient and not recommended unless accompanied by specific findings suggestive of malignancy. The present article discusses the supplementary findings that may justify malignancy evaluation.

  7. Power spectral analysis of mammographic parenchymal patterns

    NASA Astrophysics Data System (ADS)

    Li, Hui; Giger, Maryellen L.; Olopade, Olufunmilayo I.

    2006-03-01

    Mammographic density and parenchymal patterns have been shown to be associated with the risk of developing breast cancer. Two groups of women: gene-mutation carriers and low-risk women were included in this study. Power spectral analysis was performed within parenchymal regions of 172 digitized craniocaudal normal mammograms of the BRCA1/BRCA2 gene-mutation carriers and those of women at low-risk of developing breast cancer. The power law spectrum of the form, P(f)=B/f β was evaluated for the mammographic patterns. Receiver Operating Characteristic (ROC) analysis was used to assess the performance of exponent β as a decision variable in the task of distinguishing between high and low-risk subjects. Power spectral analysis of mammograms demonstrated that mammographic parenchymal patterns have a power-law spectrum of the form, P(f)=B/f β where f is radial spatial frequency, with the average β values of 2.92 and 2.47 for the gene-mutation carriers and for the low-risk women, respectively. A z values of 0.90 and 0.89 were achieved in distinguishing between the gene-mutation carriers and the low-risk women with the individual image β value as the decision variable in the entire database and the age-matched group, respectively.

  8. Occult Macular Dystrophy

    PubMed Central

    Sayman Muslubaş, Işıl; Arf, Serra; Hocaoğlu, Mümin; Özdemir, Hakan; Karaçorlu, Murat

    2016-01-01

    Occult macular dystrophy is an inherited macular dystrophy characterized by a progressive decline of bilateral visual acuity with normal fundus appearance, fluorescein angiogram and full-field electroretinogram. This case report presents a 20-year-old female patient with bilateral progressive decline of visual acuity for six years. Her visual acuity was 3-4/10 in both eyes. Anterior segment and fundus examination, fluorescein angiogram and full-field electroretinogram were normal. She could read all Ishihara pseudoisochromatic plates. Fundus autofluorescence imaging was normal. There was a mild central hyporeflectance on fundus infrared reflectance imaging in both eyes. Reduced foveal thickness and alterations of the photoreceptor inner and outer segment junction were observed by optical coherence tomography in both eyes. Central scotoma was also found by microperimetry and reduced central response was revealed by multifocal electroretinogram in both eyes. These findings are consistent with the clinical characteristics of occult macular dystrophy. PMID:27800268

  9. The Pinhole/Occulter Facility

    NASA Technical Reports Server (NTRS)

    Tandberg-Hanssen, E. A. (Editor); Hudson, H. S. (Editor); Dabbs, J. R. (Editor); Baity, W. A. (Editor)

    1983-01-01

    Scientific objectives and requirements are discussed for solar X-ray observations, coronagraph observations, studies of coronal particle acceleration, and cosmic X-ray observations. Improved sensitivity and resolution can be provided for these studies using the pinhole/occulter facility which consists of a self-deployed boom of 50 m length separating an occulter plane from a detector plane. The X-ray detectors and coronagraphic optics mounted on the detector plane are analogous to the focal plane instrumentation of an ordinary telescope except that they use the occulter only for providing a shadow pattern. The occulter plane is passive and has no electrical interface with the rest of the facility.

  10. Characterization of difference of Gaussian filters in the detection of mammographic regions

    SciTech Connect

    Catarious, David M. Jr.; Baydush, Alan H.; Floyd, Carey E. Jr.

    2006-11-15

    In this article, we present a characterization of the effect of difference of Gaussians (DoG) filters in the detection of mammographic regions. DoG filters have been used previously in mammographic mass computer-aided detection (CAD) systems. As DoG filters are constructed from the subtraction of two bivariate Gaussian distributions, they require the specification of three parameters: the size of the filter template and the standard deviations of the constituent Gaussians. The influence of these three parameters in the detection of mammographic masses has not been characterized. In this work, we aim to determine how the parameters affect (1) the physical descriptors of the detected regions (2) the true and false positive rates, and (3) the classification performance of the individual descriptors. To this end, 30 DoG filters are created from the combination of three template sizes and four values for each of the Gaussians' standard deviations. The filters are used to detect regions in a study database of 181 craniocaudal-view mammograms extracted from the Digital Database for Screening Mammography. To describe the physical characteristics of the identified regions, morphological and textural features are extracted from each of the detected regions. Differences in the mean values of the features caused by altering the DoG parameters are examined through statistical and empirical comparisons. The parameters' effects on the true and false positive rate are determined by examining the mean malignant sensitivities and false positives per image (FPpI). Finally, the effect on the classification performance is described by examining the variation in FPpI at the point where 81% of the malignant masses in the study database are detected. Overall, the findings of the study indicate that increasing the standard deviations of the Gaussians used to construct a DoG filter results in a dramatic decrease in the number of regions identified at the expense of missing a small number of

  11. Diagnostic performance with enhanced digital mammographic films

    NASA Astrophysics Data System (ADS)

    Flynn, Michael J.; Chen, Ji; Rebner, Murray; Windham, Joe P.

    1993-06-01

    Digital storage and display of mammograms could significantly improve operations in breast cancer screening programs. If mammographic films are scanned with high performance instruments, enhanced display and/or computer-aided diagnosis may improve diagnostic performance. We are studying observer performance with digital mammograms printed with 1.9X magnification, skin line equalization, and background masking. The purpose of the study is to establish that mammograms can be digitized with no loss in quality and displayed so as to improve observer performance. Performance measures of interest include diagnostic accuracy and interpretation time.

  12. The Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Russell, James M., III; Gordley, Larry L.; Park, Jae H.; Drayson, S. R.; Hesketh, W. D.; Cicerone, Ralph J.; Tuck, Adrian F.; Frederick, John E.; Harries, John E.; Crutzen, Paul J.

    1993-01-01

    The Halogen Occultation Experiment (HALOE) uses solar occultation to measure vertical profiles of O3, HCl, HF, CH4, H2O, NO, NO2, aerosol extinction, and temperature versus pressure with an instantaneous vertical field of view of 1.6 km at the earth limb. Latitudinal coverage is from 80 deg S to 80 deg N over the course of 1 year and includes extensive observations of the Antarctic region during spring. The altitude range of the measurements extends from about 15 km to about 60-130 km, depending on channel. Experiment operations have been essentially flawless, and all performance criteria either meet or exceed specifications. Internal data consistency checks, comparisons with correlative measurements, and qualitative comparisons with 1985 atmospheric trace molecule spectroscopy (ATMOS) results are in good agreement. Examples of pressure versus latitude cross sections and a global orthographic projection for the September 21 to October 15, 1992, period show the utility of CH4, HF, and H2O as tracers, the occurrence of dehydration in the Antarctic lower stratosphere, the presence of the water vapor hygropause in the tropics, evidence of Antarctic air in the tropics, the influence of Hadley tropical upwelling, and the first global distribution of HCl, HF, and NO throughout the stratosphere. Nitric oxide measurements extend through the lower thermosphere.

  13. Uranus occults SAO158687. [stellar occultation and planetary parametric observation

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.; Veverka, J.; Millis, R. L.

    1977-01-01

    Experience gained in obtaining atmospheric parameters, oblatenesses, and diameters of Jupiter and Mars from recent stellar occultations by these planets is used to predict what can be learned from the March 1977 occultation of the star SAO158687 by Uranus. The spectra of this star and Uranus are compared to indicate the relative instrument intensities of the two objects, the four passbands where the relative intensities are most nearly equal are listed, and expected photon fluxes from the star are computed on the assumption that it has UBVRI colors appropriate for a K5 main-sequence object. It is shown that low photon noise errors can be achieved by choosing appropriate passbands for observation, and the rms error expected for the Uranus temperature profiles obtained from the occultation light curves is calculated. It is suggested that observers of this occultation should record their data digitally for optimum time resolution.

  14. Pinhole occulter experiment

    NASA Technical Reports Server (NTRS)

    Ring, Jeff; Pflug, John

    1987-01-01

    Viewgraphs and charts from a briefing summarize the accomplishments, results, conclusions, and recommendations of a feasibility study using the Pinhole Occulter Facility (POF). Accomplishments for 1986 include: (1) improved IPS Gimbal Model; (2) improved Crew Motion Disturbance Model; (3) use of existing shuttle on-orbit simulation to study the effects of orbiter attitude deadband size on POF performance; (4) increased understanding of maximum performance expected from current actuator/sensor set; (5) use of TREETOPS nonlinear time domain program to obtain system dynamics describing the complex multibody flexible structures; (6) use of HONEY-X design tool to design and evaluate multivariable compensator for stability, robustness, and performance; (7) application of state-of-the-art compensator design methodology Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR); and (8) examination of tolerance required on knowledge of the POF boom flexible mode frequencies to insure stability, using structure uncertainty analysis.

  15. Pinhole occulter experiment

    NASA Astrophysics Data System (ADS)

    Ring, Jeff; Pflug, John

    1987-02-01

    Viewgraphs and charts from a briefing summarize the accomplishments, results, conclusions, and recommendations of a feasibility study using the Pinhole Occulter Facility (POF). Accomplishments for 1986 include: (1) improved IPS Gimbal Model; (2) improved Crew Motion Disturbance Model; (3) use of existing shuttle on-orbit simulation to study the effects of orbiter attitude deadband size on POF performance; (4) increased understanding of maximum performance expected from current actuator/sensor set; (5) use of TREETOPS nonlinear time domain program to obtain system dynamics describing the complex multibody flexible structures; (6) use of HONEY-X design tool to design and evaluate multivariable compensator for stability, robustness, and performance; (7) application of state-of-the-art compensator design methodology Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR); and (8) examination of tolerance required on knowledge of the POF boom flexible mode frequencies to insure stability, using structure uncertainty analysis.

  16. Paraneoplastic retinopathy associated with occult bladder cancer

    PubMed Central

    Nivean, M; Muttuvelu, Danson V; Afzelius, Pia; Berman, Dalia C

    2016-01-01

    The aim was to report the first case of cancer-associated retinopathy (CAR) presenting before bladder cancer diagnosis. A 71-year-old woman with a history of bilateral vision loss underwent subsequent complete ophthalmic examination include a fluorescein angiography, full-field electroretinogram (ERG), serology including serum antibodies for CAR, and positron emission tomography-computed tomography (PET-CT) scan. The patient was diagnosed with bladder carcinoma revealed by PET-CT. Timely recognition of this entity may be crucial for an increased patient survival thus adult onset progressive photoreceptor dysfunction, confirmed by ERG, should alert to a possible remote effect of known or occult malignancy. In the latter, PET-CT may be exploited as a powerful diagnostic tool. PMID:27146943

  17. Paraneoplastic retinopathy associated with occult bladder cancer.

    PubMed

    Nivean, M; Muttuvelu, Danson V; Afzelius, Pia; Berman, Dalia C

    2016-03-01

    The aim was to report the first case of cancer-associated retinopathy (CAR) presenting before bladder cancer diagnosis. A 71-year-old woman with a history of bilateral vision loss underwent subsequent complete ophthalmic examination include a fluorescein angiography, full-field electroretinogram (ERG), serology including serum antibodies for CAR, and positron emission tomography-computed tomography (PET-CT) scan. The patient was diagnosed with bladder carcinoma revealed by PET-CT. Timely recognition of this entity may be crucial for an increased patient survival thus adult onset progressive photoreceptor dysfunction, confirmed by ERG, should alert to a possible remote effect of known or occult malignancy. In the latter, PET-CT may be exploited as a powerful diagnostic tool. PMID:27146943

  18. Reduction of false-positive recalls using a computerized mammographic image feature analysis scheme

    NASA Astrophysics Data System (ADS)

    Tan, Maxine; Pu, Jiantao; Zheng, Bin

    2014-08-01

    The high false-positive recall rate is one of the major dilemmas that significantly reduce the efficacy of screening mammography, which harms a large fraction of women and increases healthcare cost. This study aims to investigate the feasibility of helping reduce false-positive recalls by developing a new computer-aided diagnosis (CAD) scheme based on the analysis of global mammographic texture and density features computed from four-view images. Our database includes full-field digital mammography (FFDM) images acquired from 1052 recalled women (669 positive for cancer and 383 benign). Each case has four images: two craniocaudal (CC) and two mediolateral oblique (MLO) views. Our CAD scheme first computed global texture features related to the mammographic density distribution on the segmented breast regions of four images. Second, the computed features were given to two artificial neural network (ANN) classifiers that were separately trained and tested in a ten-fold cross-validation scheme on CC and MLO view images, respectively. Finally, two ANN classification scores were combined using a new adaptive scoring fusion method that automatically determined the optimal weights to assign to both views. CAD performance was tested using the area under a receiver operating characteristic curve (AUC). The AUC = 0.793  ±  0.026 was obtained for this four-view CAD scheme, which was significantly higher at the 5% significance level than the AUCs achieved when using only CC (p = 0.025) or MLO (p = 0.0004) view images, respectively. This study demonstrates that a quantitative assessment of global mammographic image texture and density features could provide useful and/or supplementary information to classify between malignant and benign cases among the recalled cases, which may eventually help reduce the false-positive recall rate in screening mammography.

  19. The Occult: Diabolica to Alchemists

    ERIC Educational Resources Information Center

    Delaney, Oliver J.

    1971-01-01

    The 91 items in this bibliography deal with works of occult science. The material is subdivided into biographies, dictionaries, encyclopedias, handbooks, noteworthy histories, indices, annuals, and a few miscellany works with treatises. (95 references) (Author)

  20. KPNO LUNAR OCCULTATION SUMMARY. III

    SciTech Connect

    Schmidtke, P. C.; Africano, J. L.

    2011-01-15

    The results for 251 lunar occultation events recorded at Kitt Peak National Observatory are presented, including 20 observations of known or suspected double stars and five measurements of stars with resolved angular diameters.

  1. Image resampling effects in mammographic image simulation.

    PubMed

    Yip, M; Mackenzie, A; Lewis, E; Dance, D R; Young, K C; Christmas, W; Wells, K

    2011-11-21

    This work describes the theory of resampling effects within the context of image simulation for mammographic images. The process of digitization associated with using digital imaging technology needs to be correctly addressed in any image simulation process. Failure to do so can lead to overblurring in the final synthetic image. A method for weighted neighbourhood averaging is described for non-integer scaling factors in resampling images. The use of the method is demonstrated by comparing simulated and real images of an edge test object acquired on two clinical mammography systems. Images were simulated using two setups: from idealized images and from images obtained with clinical systems. A Gaussian interpolation method is proposed as a single-step solution to modelling blurring filters for the simulation process.

  2. A review of the cost-effectiveness of Tc-99m sestamibi scintimammography in diagnosis of breast cancer in Taiwanese women with indeterminate mammographically dense breast.

    PubMed

    Chen, Yi-Shan; Wang, Wei-Hua; Chan, Tam; Sun, Shung-Shung; Kao, Albert

    2002-11-01

    In general, biopsy is the preferred management method for women with indeterminate mammographically dense breasts. In this review, we describe a decision analysis model comparing technetium-99m methoxyisobutylisonitrile (Tc-99m sestamibi) scintimammography and excisional biopsy as breast cancer evaluation strategies for hypothetical cohorts of estimated 16,000-40,000 women with indeterminate mammographic probability of malignancy because of mammographically dense breasts. In cost-effectiveness analysis, quantitative decision tree sensitivity analysis was used to compare the conventional excision biopsy alone strategy (strategy A) with decision strategy for screening with Tc-99m sestamibi scintimammography before excision biopsy (strategy B) after an indeterminate mammogram. Strategy B showed a cost saving of US dollars 649,600-1,624,000 in reducing the cost of unnecessary biopsies. The total cost of strategy B showed a cost saving of US dollars 123,075-307,776 compared to strategy A. The analysis data indicate that Tc-99m sestamibi scintimammography can save the cost of unnecessary biopsies in Taiwanese women with non-diagnostic mammogram because of mammographically dense breasts. PMID:12356511

  3. Circulating serum xenoestrogens and mammographic breast density

    PubMed Central

    2013-01-01

    Introduction Humans are widely exposed to estrogenically active phthalates, parabens, and phenols, raising concerns about potential effects on breast tissue and breast cancer risk. We sought to determine the association of circulating serum levels of these chemicals (reflecting recent exposure) with mammographic breast density (a marker of breast cancer risk). Methods We recruited postmenopausal women aged 55 to 70 years from mammography clinics in Madison, Wisconsin (N = 264). Subjects completed a questionnaire and provided a blood sample that was analyzed for mono-ethyl phthalate, mono-butyl phthalate, mono-benzyl phthalate, butyl paraben, propyl paraben, octylphenol, nonylphenol, and bisphenol A (BPA). Percentage breast density was measured from mammograms by using a computer-assisted thresholding method. Results Serum BPA was positively associated with mammographic breast density after adjusting for age, body mass index, and other potentially confounding factors. Mean percentage density was 12.6% (95% confidence interval (CI), 11.4 to 14.0) among the 193 women with nondetectable BPA levels, 13.7% (95% CI, 10.7 to 17.1) among the 35 women with detectable levels below the median (<0.55 ng/ml), and 17.6% (95% CI, 14.1 to 21.5) among the 34 women with detectable levels above the median (>0.55 ng/ml; Ptrend = 0.01). Percentage breast density was also elevated (18.2%; 95% CI, 13.4 to 23.7) among the 18 women with serum mono-ethyl phthalate above the median detected level (>3.77 ng/ml) compared with women with nondetectable BPA levels (13.1%; 95% CI, 11.9 to 14.3; Ptrend = 0.07). No other chemicals demonstrated associations with percentage breast density. Conclusions Postmenopausal women with high serum levels of BPA and mono-ethyl phthalate had elevated breast density. Further investigation of the impact of BPA and mono-ethyl phthalate on breast cancer risk by using repeated serum measurements or other markers of xenoestrogen exposure are needed. PMID:23710608

  4. Home Use Tests: Fecal Occult Blood

    MedlinePlus

    ... Procedures In Vitro Diagnostics Home Use Tests Fecal Occult Blood Share Tweet Linkedin Pin it More sharing ... test kit to measure the presence of hidden (occult) blood in your stool (feces). What is fecal ...

  5. Testing for Occult Heartworm Infection

    PubMed Central

    Stogdale, L.

    1984-01-01

    Heartworm infection in dogs is endemic in southern Ontario but occurs only sporadically throughout the remainder of Canada. The disease may either be associated with microfilariae in the patient's blood, a patent infection, or it may be occult. This paper describes a case of occult dirofilariasis in a dog, with emphasis on the diagnosis. A patent infection could be missed if the clinician tests an insufficient amount of blood. He should perform multiple concentration tests using either the modified Knott's technique or a filtration method. Occult infections occur in prepatent or unisexual infections, when the worms become sterile following therapy, or when the host produces antibodies that result in the destruction of the microfilariae. The recent release of a kit which detects the presence of antibodies to the adult heartworms now enables veterinarians to make an accurate diagnosis in the vast majority of dogs. PMID:17422386

  6. Occult Participation: Its Impact on Adolescent Development.

    ERIC Educational Resources Information Center

    Tennant-Clark, Cynthia M.; And Others

    1989-01-01

    Investigated relationship between occult participation, substance abuse, and level of self-esteem among 25 clinical (alcohol or drug treatment) and 25 nonclinical adolescents. Results indicated that adolescent substance abuse and occult participation were significantly related. Found significant differences between high versus low occult groups…

  7. Mammographic signs as risk factors for breast cancer.

    PubMed Central

    Boyd, N. F.; O'Sullivan, B.; Campbell, J. E.; Fishell, E.; Simor, I.; Cooke, G.; Germanson, T.

    1982-01-01

    We have carried out a case-control study to examine the relationship between mammographic signs and breast cancer. The mammographic signs assessed were prominent ducts and dysplasia. The cases were a group of 183 women with histologically verified unilateral breast cancer. The controls were a group of women attending a screening centre. Cases and controls were individually age-matched. Mammograms from the non-cancerous breast of the cases were randomly assembled with those of the controls and classified by 3 radiologists without knowledge of which films were from cases and which from controls. Mammographic dysplasia was found to be strongly associated with breast cancer, particularly in women aged less than 50. Prominent ducts were only weakly associated with breast cancer. Multivariate analysis showed that the association between dysplasia and breast cancer could not be explained on the basis of other risk factors for breast cancer, and that classification of dysplasia discriminated more strongly between cases and controls than did classification of Wolfe's mammographic patterns. These results show that mammograms contain information about risk of breast cancer. Mammographic dysplasia is strongly associated with breast cancer, is present in a substantial proportion of patients with the disease, and may offer opportunities for prevention. PMID:7059469

  8. A Review on Automatic Mammographic Density and Parenchymal Segmentation

    PubMed Central

    He, Wenda; Juette, Arne; Denton, Erika R. E.; Oliver, Arnau; Martí, Robert; Zwiggelaar, Reyer

    2015-01-01

    Breast cancer is the most frequently diagnosed cancer in women. However, the exact cause(s) of breast cancer still remains unknown. Early detection, precise identification of women at risk, and application of appropriate disease prevention measures are by far the most effective way to tackle breast cancer. There are more than 70 common genetic susceptibility factors included in the current non-image-based risk prediction models (e.g., the Gail and the Tyrer-Cuzick models). Image-based risk factors, such as mammographic densities and parenchymal patterns, have been established as biomarkers but have not been fully incorporated in the risk prediction models used for risk stratification in screening and/or measuring responsiveness to preventive approaches. Within computer aided mammography, automatic mammographic tissue segmentation methods have been developed for estimation of breast tissue composition to facilitate mammographic risk assessment. This paper presents a comprehensive review of automatic mammographic tissue segmentation methodologies developed over the past two decades and the evidence for risk assessment/density classification using segmentation. The aim of this review is to analyse how engineering advances have progressed and the impact automatic mammographic tissue segmentation has in a clinical environment, as well as to understand the current research gaps with respect to the incorporation of image-based risk factors in non-image-based risk prediction models. PMID:26171249

  9. Paget disease of the breast: mammographic, US, and MR imaging findings with pathologic correlation.

    PubMed

    Lim, Hyo Soon; Jeong, Su Jin; Lee, Ji Shin; Park, Min Ho; Kim, Jin Woong; Shin, Sang Soo; Park, Jin Gyoon; Kang, Heoung Keun

    2011-01-01

    Paget disease is a rare malignancy of the breast characterized by infiltration of the nipple epidermis by adenocarcinoma cells. The clinical features of Paget disease are characteristic and should increase the likelihood of the diagnosis being made. An important point is that more than 90% of cases of Paget disease are associated with an additional underlying breast malignancy. Paget disease is frequently associated with ductal carcinoma in situ (DCIS) in the underlying lactiferous ducts of the nipple-areolar complex; it may even be associated with DCIS or invasive breast cancer elsewhere in the breast, at least 2 cm from the nipple-areolar complex. Nevertheless, mammographic findings may be negative in up to 50% of cases. Magnetic resonance (MR) imaging can be useful in patients with Paget disease for evaluation of the nipple-areolar complex and identification of an additional underlying malignancy in the breast. The appropriate surgical treatment must be carefully selected and individualized on the basis of radiologic findings, especially those obtained with breast MR imaging.

  10. Mammographic CADx system using an image library with an intelligent agent: A pattern matching approach

    NASA Astrophysics Data System (ADS)

    Lo, Shih-Chung B.; Freedman, Matthew T.; Kinnard, Lisa; Makariou, Erini

    2006-03-01

    It is conceivable that a comprehensive clinical case library with intelligent agents can sort and render clinically similar cases and present clinically significant features to assist the radiologist in interpreting mammograms. In this study, we used a deformable vector diagram as the primary framework for matching the mammographic masses. The vector diagram provides gradient and shape features of the mass. The deformable algorithm allows flexible matching. The vector diagram was also incorporated with our newly developed delineation method using steepest changes of a probability based cost-function. Thus it allows us to automatically extract the main body and significant part of border region for pattern matching using a weighted mutual information technique. We have collected 86 mammograms. Of these cases, 46 contain a benign mass and the other 40 contain a malignant mass. Using the weighted mutual information technique on the vector diagram of the mass region, we found that the benign masses can be sorted into 6 groups except one case; the malignant masses can be sorted into 8 groups except two cases. For all 86 cases, the masses can be sorted into 13 groups except three cases. In addition, one group of benign masses and one group of malignant mass cases merged into one which contains 10 cases. Hence, the success sorting rate was 85.7% (12/14) in terms of group and was 84.9% (73/86) in terms of case, respectively.

  11. Birth weight and mammographic density among postmenopausal women in Sweden.

    PubMed

    Tamimi, Rulla M; Eriksson, Louise; Lagiou, Pagona; Czene, Kamila; Ekbom, Anders; Hsieh, Chung-Cheng; Adami, Hans-Olov; Trichopoulos, Dimitrios; Hall, Per

    2010-02-15

    Birth weight is a significant predictor of breast cancer risk in adult life and mammary gland mass could be an intermediate stage in this long process. We have studied the association of birth size measurements with mammographic density, a marker of mammary gland mass. For a population-based sample of 893 postmenopausal women without previous cancer in Sweden, we retrieved information on birth size from birth records and their most recent mammography. Film mammograms of the medio-lateral oblique view were digitized and the Cumulus software was used for computer-assisted semi-automated thresholding of mammographic density. Results were analyzed using generalized linear models controlling for possible confounders. Mean percent mammographic density increased when comparing the extreme categories of birth weight (from 15.6% to 18.6%) and head circumference (from 15.5% to 20.4%), and the corresponding linear trends were statistically significant (p values 0.02 and 0.007, respectively). The associations were particularly strong when the cutoff for high versus low mammographic density was set at the relatively high value of 50%. Compared to women weighing 3001-3500 grams at birth, women with birth weights >4000g were at almost 3-fold risk of developing high mammographic density (odds ratio: 2.9, 95% confidence interval 1.1 to 7.9). No association with mammographic density was evident with respect to birth length which, however, is known to be less accurately measured. These results indicate that adult breast density, a powerful predictor of breast cancer risk, has intrauterine roots, as reflected in birth size. PMID:19642103

  12. Occult breast lesions: A comparison between radioguided occult lesion localisation (ROLL) vs. wire-guided lumpectomy (WGL).

    PubMed

    Nadeem, R; Chagla, L S; Harris, O; Desmond, S; Thind, R; Titterrell, C; Audisio, R A

    2005-08-01

    Mammographic screening increases the number of impalpable breast cancers requiring surgical excision. It is important to optimise the localisation technique to remove the smallest amount of tissue, still adequately excising the lesion. The last 65 wire-guided lumpectomies (WGLs) were compared vs. the first 65 radioguided occult lesion localisations (ROLLs) performed for impalpable breast cancers. Data collection included patient's age, radiological abnormality, pre-operative core biopsy, type of primary surgery, length of localisation and excision, hospital stay, cancer size, weight and volume of the excised specimen, clearance margins. All patients were successfully localised with ROLL and WGL. Localisation time was reduced with ROLL (P<0.001). Clear margins were achieved in 83% ROLLs and 57% WGLs (P=0.001). Pathological cancer size and specimen weight were similar in both groups, although the specimen volume was slightly smaller for ROLL. A total of 74% ROLLs had excellent cosmetic outcomes and 26% good, vs. 55% excellent and 45% good in WGLs. A larger amount of normal breast tissue was excised with WGL, without achieving any better cancer clearance. ROLL provides a feasible alternative to WGL. This quick and simple technique achieves an improved rate of clear margins.

  13. The Pinhole/Occulter facility

    NASA Technical Reports Server (NTRS)

    Dabbs, J. R.; Tandberg-Hanssen, E. A.; Hudson, H. S.

    1982-01-01

    The outer solar atmosphere exhibits a great variety of dynamic and energetic plasma phenomena, from the catastrophic energy release of solar flares to the steady acceleration of the solar wind. The Pinhole/Occulter Facility contains the instruments necessary for broadband X-ray imaging, combined with simultaneous ultraviolet and white light spectroscopy and imaging.

  14. Surveillance for gastrointestinal malignancies

    PubMed Central

    Tiwari, Ashish K; Laird-Fick, Heather S; Wali, Ramesh K; Roy, Hemant K

    2012-01-01

    Gastrointestinal (GI) malignancies are notorious for frequently progressing to advanced stages even in the absence of serious symptoms, thus leading to delayed diagnoses and dismal prognoses. Secondary prevention of GI malignancies through early detection and treatment of cancer-precursor/premalignant lesions, therefore, is recognized as an effective cancer prevention strategy. In order to efficiently detect these lesions, systemic application of screening tests (surveillance) is needed. However, most of the currently used non-invasive screening tests for GI malignancies (for example, serum markers such as alpha-fetoprotein for hepatocellular carcinoma, and fecal occult blood test, for colon cancer) are only modestly effective necessitating the use of highly invasive endoscopy-based procedures, such as esophagogastroduodenoscopy and colonoscopy for screening purposes. Even for hepatocellular carcinoma where non-invasive imaging (ultrasonography) has become a standard screening tool, the need for repeated liver biopsies of suspicious liver nodules for histopathological confirmation can’t be avoided. The invasive nature and high-cost associated with these screening tools hinders implementation of GI cancer screening programs. Moreover, only a small fraction of general population is truly predisposed to developing GI malignancies, and indeed needs surveillance. To spare the average-risk individuals from superfluous invasive procedures and achieve an economically viable model of cancer prevention, it’s important to identify cohorts in general population that are at substantially high risk of developing GI malignancies (risk-stratification), and select suitable screening tests for surveillance in these cohorts. We herein provide a brief overview of such high-risk cohorts for different GI malignancies, and the screening strategies that have commonly been employed for surveillance purpose in them. PMID:22969223

  15. Mammographic computer-aided detection systems.

    PubMed

    2003-04-01

    While mammography is regarded as the best means available to screen for breast cancer, reading mammograms is a tedious, error-prone task. Given the repetitiveness of the process and the fact that less than 1% of mammograms in the average screening population contain cancer, it's no wonder that a significant number of breast cancers--about 28%--are missed by radiologists. The fact that human error is such a significant obstacle makes mammography screening an ideal application for computer-aided detection (CAD) systems. CAD systems serve as a "second pair of eyes" to ensure that radiologists don't miss a suspect area on an image. They analyze patterns on a digitized mammographic image, identify regions that may contain an abnormality indicating cancer, and mark these regions. The marks are then inspected and classified by a radiologist. But CAD systems provide no diagnosis of any kind--it's up to the radiologist to analyze the marked area and decide if it shows cancer. In this Evaluation, we describe the challenges posed by screening mammography, the operating principles and overall efficacy of CAD systems, and the characteristics to consider when purchasing a system. We also compare the performance of two commercially available systems, iCAD's MammoReader and R2's ImageChecker. Because the two systems offer comparable sensitivity, our judgments are based on other performance characteristics, including their ease of use, the number of false marks they produce, the degree to which they can integrate with hospital information systems, and their processing speed.

  16. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  17. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  18. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  19. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  20. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  1. Breast image pre-processing for mammographic tissue segmentation.

    PubMed

    He, Wenda; Hogg, Peter; Juette, Arne; Denton, Erika R E; Zwiggelaar, Reyer

    2015-12-01

    During mammographic image acquisition, a compression paddle is used to even the breast thickness in order to obtain optimal image quality. Clinical observation has indicated that some mammograms may exhibit abrupt intensity change and low visibility of tissue structures in the breast peripheral areas. Such appearance discrepancies can affect image interpretation and may not be desirable for computer aided mammography, leading to incorrect diagnosis and/or detection which can have a negative impact on sensitivity and specificity of screening mammography. This paper describes a novel mammographic image pre-processing method to improve image quality for analysis. An image selection process is incorporated to better target problematic images. The processed images show improved mammographic appearances not only in the breast periphery but also across the mammograms. Mammographic segmentation and risk/density classification were performed to facilitate a quantitative and qualitative evaluation. When using the processed images, the results indicated more anatomically correct segmentation in tissue specific areas, and subsequently better classification accuracies were achieved. Visual assessments were conducted in a clinical environment to determine the quality of the processed images and the resultant segmentation. The developed method has shown promising results. It is expected to be useful in early breast cancer detection, risk-stratified screening, and aiding radiologists in the process of decision making prior to surgery and/or treatment.

  2. Sensitivity of Noncommercial Computer-aided Detection System for Mammographic Breast Cancer Detection: Pilot Clinical Trial

    PubMed Central

    Helvie, Mark A.; Hadjiiski, Lubomir; Makariou, Erini; Chan, Heang-Ping; Petrick, Nicholas; Sahiner, Berkman; Lo, Shih-Chung B.; Freedman, Matthew; Adler, Dorit; Bailey, Janet; Blane, Caroline; Hoff, Donna; Hunt, Karen; Joynt, Lynn; Klein, Katherine; Paramagul, Chintana; Patterson, Stephanie K.; Roubidoux, Marilyn A.

    2009-01-01

    PURPOSE To evaluate a noncommercial computer-aided detection (CAD) program for breast cancer detection with screening mammography. MATERIALS AND METHODS A CAD program was developed for mammographic breast cancer detection. The program was applied to 2,389 patients’ screening mammograms at two geographically remote academic institutions (institutions A and B). Thirteen radiologists who specialized in breast imaging participated in this pilot study. For each case, the individual radiologist performed a prospective Breast Imaging Reporting and Data System (BI-RADS) assessment after viewing of the screening mammogram. Subsequently, the radiologist was shown CAD results and rendered a second BI-RADS assessment by using knowledge of both mammographic appearance and CAD results. Outcome analysis of results of examination in patients recalled for a repeat examination, of biopsy, and of 1-year follow-up examination was recorded. Correct detection with CAD included a computer-generated mark indicating a possible malignancy on craniocaudal or mediolateral oblique views or both. RESULTS Eleven (0.46%) of 2,389 patients had mammographically detected nonpalpable breast cancers. Ten (91%) of 11 (95% CI: 74%, 100%) cancers were correctly identified with CAD. Radiologist sensitivity without CAD was 91% (10 of 11; 95% CI: 74%, 100%). In 1,077 patients, follow-up findings were documented at 1 year. Five (0.46%) patients developed cancers, which were found on subsequent screening mammograms. The area where the cancers developed in two (40%) of these five patients was marked (true-positive finding) by the computer in the preceding year. Because of CAD results, a 9.7% increase in recall rate from 14.4% (344 of 2,389) to 15.8% (378 of 2,389) occurred. Radiologists’ recall rate of study patients prior to use of CAD was 31% higher than the average rate for nonstudy cases (10.3%) during the same time period at institution A. CONCLUSION Performance of the CAD program had a very high

  3. Breast MR Imaging for Equivocal Mammographic Findings: Help or Hindrance?

    PubMed

    Giess, Catherine S; Chikarmane, Sona A; Sippo, Dorothy A; Birdwell, Robyn L

    2016-01-01

    Breast magnetic resonance (MR) imaging, because of its extremely high sensitivity in detecting invasive breast cancers, is sometimes used as a diagnostic tool to evaluate equivocal mammographic findings. However, breast MR imaging should never substitute for a complete diagnostic evaluation or for biopsy of suspected, localizable suspicious mammographic lesions, whenever possible. The modality's high cost, in addition to only moderate specificity, mandate that radiologists use it sparingly and with discrimination for problematic mammographic findings. It is rare that the reality or significance of a noncalcified mammographic finding remains equivocal or problematic at diagnostic mammography evaluation, which usually includes targeted ultrasonography (US). There are several reasons for this infrequent occurrence: (a) an asymmetry may persist on diagnostic views but be visible only on craniocaudal or mediolateral oblique projections, precluding three-dimensional localization for US or biopsy, or a lesion may persist on some diagnostic spot views but dissipate or efface on others; (b) uncertainty may exist as to whether apparent change is clinically important or owing to technical factors such as compression or positioning differences; or (c) a lesion may be suspected but biopsy options are limited owing to lack of a US correlate and lesion inaccessibility for stereotactic biopsy, or biopsy of a vague or questionably real lesion has been attempted unsuccessfully. This article will discuss the indications for problem-solving MR imaging for equivocal mammographic findings, present cases illustrating appropriate and inappropriate uses of problem-solving MR imaging, and present false-positive and false-negative cases affecting the specificity of breast MR imaging. (©)RSNA, 2016. PMID:27284757

  4. Triton stellar occultation candidates - 1992-1994

    NASA Technical Reports Server (NTRS)

    Mcdonald, S. W.; Elliot, J. T.

    1992-01-01

    A search for Triton stellar occultation candidates for the period 1992-1994 has been completed with CCD strip-scanning observations. The search reached an R magnitude of about 17.4 and found 129 candidates within 1.5 arcsec of Triton's ephemeris during this period. Of these events, around 30 occultations are expected to be visible from the earth, indicating that a number of Triton occultation events should be visible from major observatories. Even the faintest of the present candidate events could produce useful occultation data if observed with a large enough telescope. The present astrometric accuracy is inadequate to identify which of these appulse events will produce occultations on the earth; further astrometry is needed to refine the predictions for positive occultation identification. To aid in selecting candidates for additional astrometric and photometric studies, finder charts and earth-based visibility charts for each event are included.

  5. IUVS/MAVEN Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Gröller, Hannes; Yelle, Roger; Montmessin, Franck; Lacombe, Gaetan; Schneider, Nicholas M.; Deighan, Justin; Jain, Sonal; Nakagawa, Hiromu; Jakosky, Bruce

    2016-10-01

    We present the latest results from stellar occultations observed with the Imaging Ultraviolet Spectrograph (IUVS) instrument on board of Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. So far 9 campaigns have been executed on average every two months since MAVEN began orbiting Mars. Approximately 50 occultations are recorded in each campaign. The IUVS instrument observes in two spectral regions, the far- and mid-UV. The FUV channel covers wavelengths from 110 to 190 nm and the MUV channel from 170 to 350 nm. By combining those two channels we cover the whole altitude range starting from around 30 km to 150 km. We present the geometric dependent CO2, O2, and O3 number densities from these occultations. The derived O2 mixing ratio varies between 1.5 × 10-3 and 5 × 10-3. In some of the MUV occultations we also can see aerosol extinction. In addition we present temperatures derived from the CO2 densities assuming hydrostatic equilibrium. We retrieved mean temperatures of around 180 K at lower altitudes, which decreasing with altitudes down to a mean of around 130 K at higher altitudes. We see a constantly cold layer with temperatures of 105 – 120 K at a pressure level at roughly 7 × 10-6 Pa, equivalent to an altitude of around 140 km. We also discuss possible wave structures with amplitudes between 5 and 15 K and wavelengths between 10 and 15 km in the obtained temperature profiles. The temperature profiles, retrieved with the IUVS instrument, are mostly in agreement with predicted values from the Mars Climate Database model, except where we see the cold layer around 140 km.

  6. Computer-aided classification of mammographic masses using the deep learning technology: a preliminary study

    NASA Astrophysics Data System (ADS)

    Qiu, Yuchen; Yan, Shiju; Tan, Maxine; Cheng, Samuel; Liu, Hong; Zheng, Bin

    2016-03-01

    Although mammography is the only clinically acceptable imaging modality used in the population-based breast cancer screening, its efficacy is quite controversy. One of the major challenges is how to help radiologists more accurately classify between benign and malignant lesions. The purpose of this study is to investigate a new mammographic mass classification scheme based on a deep learning method. In this study, we used an image dataset involving 560 regions of interest (ROIs) extracted from digital mammograms, which includes 280 malignant and 280 benign mass ROIs, respectively. An eight layer deep learning network was applied, which employs three pairs of convolution-max-pooling layers for automatic feature extraction and a multiple layer perception (MLP) classifier for feature categorization. In order to improve robustness of selected features, each convolution layer is connected with a max-pooling layer. A number of 20, 10, and 5 feature maps were utilized for the 1st, 2nd and 3rd convolution layer, respectively. The convolution networks are followed by a MLP classifier, which generates a classification score to predict likelihood of a ROI depicting a malignant mass. Among 560 ROIs, 420 ROIs were used as a training dataset and the remaining 140 ROIs were used as a validation dataset. The result shows that the new deep learning based classifier yielded an area under the receiver operation characteristic curve (AUC) of 0.810+/-0.036. This study demonstrated the potential superiority of using a deep learning based classifier to distinguish malignant and benign breast masses without segmenting the lesions and extracting the pre-defined image features.

  7. The Pinhole/Occulter Facility

    NASA Technical Reports Server (NTRS)

    Hudson, H. S.; Kohl, J. L.; Lin, R. P.; Macqueen, R. M.; Tandberg-Hanssen, E.; Pabbs, J. R.

    1981-01-01

    A large occulting system in space can be used for high resolution X-ray observations and for large aperture coronagraphic observations in visible and UV light. The X-ray observations can combine high angular resolution in hand (10 keV) X-radiation with the high sensitivity of a multiple pinhole camera, and can permit sensitive observations of bremsstrahlung from nonthermal particles in the corona. The large aperture coronagraphs have two major advantages: high angular resolution and good photon collection. This will permit observations of small scale structures in the corona for the first time and will give sufficient counting rates above the coronal background rates for sensitive diagnostic analysis of intensities and line profiles for coronal structures in the solar wind acceleration region. The technical basis for performing observations with a large occulting system in these three wavelength ranges is described as well as a pinhole/occulter facility presently being considered for Spacelab. Some indications about future developments are included.

  8. Automated classification of mammographic microcalcifications by using artificial neural networks and ACR BI-RADS criteria

    NASA Astrophysics Data System (ADS)

    Hara, Takeshi; Yamada, Akitsugu; Fujita, Hiroshi; Iwase, Takuji; Endo, Tokiko

    2001-07-01

    We have been developing an automated detection scheme for mammographic microcalcifications as a part of computer-assisted diagnosis (CAD) system. The purpose of this study is to develop an automated classification technique for the detected microcalcifications. Types of distributions of calcifications are known to be significantly relevant to their probability of malignancy, and are described on ACR BI-RADS (Breast Imaging Reporting and Data System) , in which five typical types are illustrated as diffuse/scattered, regional, segmental, linear and clustered. Detected microcalcifications by our CAD system are classified automatically into one of their five types based on shape of grouped microcalcifications and the number of microcalcifications within the grouped area. The type of distribution and other general image feature values are analyzed by artificial neural networks (ANNs) and the probability of malignancy is indicated. Eighty mammograms with biopsy-proven microcalcifications were employed and digitized with a laser scanner at a pixel size of 0.1mm and 12-bit density depth. The sensitivity and specificity were 93% and 93%, respectively. The performance was significantly improved in comparison with the case that the five criteria in BI-RADS were not employed.

  9. Scaling Relation for Occulter Manufacturing Errors

    NASA Technical Reports Server (NTRS)

    Sirbu, Dan; Shaklan, Stuart B.; Kasdin, N. Jeremy; Vanderbei, Robert J.

    2015-01-01

    An external occulter is a spacecraft own along the line-of-sight of a space telescope to suppress starlight and enable high-contrast direct imaging of exoplanets. The shape of an external occulter must be specially designed to optimally suppress starlight and deviations from the ideal shape due to manufacturing errors can result loss of suppression in the shadow. Due to the long separation distances and large dimensions involved for a space occulter, laboratory testing is conducted with scaled versions of occulters etched on silicon wafers. Using numerical simulations for a flight Fresnel occulter design, we show how the suppression performance of an occulter mask scales with the available propagation distance for expected random manufacturing defects along the edge of the occulter petal. We derive an analytical model for predicting performance due to such manufacturing defects across the petal edges of an occulter mask and compare this with the numerical simulations. We discuss the scaling of an extended occulter test-bed.

  10. Occult hemorrhage in children with severe ITP.

    PubMed

    Flores, Adolfo; Buchanan, George R

    2016-03-01

    Little is known about the frequency and significance of clinically unapparent or occult hemorrhage in ITP. Therefore, we prospectively explored the sites and frequency of occult bleeding in children with severe ITP at diagnosis or upon symptomatic relapse in a prospective, single-institution cohort study of patients ≤ 18 years of age and a platelet count ≤ 10,000/mm(3) . Data collected included bleeding severity assessment, urinalysis, fecal occult blood testing, and non-contrast brain MRI. Stool and urine samples were tested within 7 days of diagnosis or symptomatic relapse. Three months after diagnosis or relapse a noncontrast brain MRI evaluated hemosiderin deposits resulting from prior localized hemorrhage. Fifty-two ITP patients were enrolled with a mean platelet count of 4,000/mm(3) . A significant occurrence of occult hemorrhage was identified in the urine (27%) compared with clinically overt hematuria (0.91%, P < 0.0005). CNS microbleeding in the superficial cortex of the left frontal lobe was identified in one child with occult bleeding in the urinary tract. There was no relationship between occult hemorrhage and bleeding manifestations on physical examination. Occult hemorrhage was not a harbinger of subsequent bleeding. Our findings suggest that occult hemorrhage occurs with greater frequency than overt bleeding in children with severe ITP. CNS microbleeding is a potential risk in this patient population. Assessment of brain microbleeds and microscopic hematuria in this patient population require additional study.

  11. Mammographical mass detection and classification using local seed region growing-spherical wavelet transform (LSRG-SWT) hybrid scheme.

    PubMed

    Görgel, Pelin; Sertbas, Ahmet; Ucan, Osman N

    2013-07-01

    The purpose of this study is to implement accurate methods of detection and classification of benign and malignant breast masses in mammograms. Our new proposed method, which can be used as a diagnostic tool, is denoted Local Seed Region Growing-Spherical Wavelet Transform (LSRG-SWT), and consists of four steps. The first step is homomorphic filtering for enhancement, and the second is detection of the region of interests (ROIs) using a Local Seed Region Growing (LSRG) algorithm, which we developed. The third step incoporates Spherical Wavelet Transform (SWT) and feature extraction. Finally the fourth step is classification, which consists of two sequential components: the 1st classification distinguishes the ROIs as either mass or non-mass and the 2nd classification distinguishes the masses as either benign or malignant using a Support Vector Machine (SVM). The mammograms used in this study were acquired from the hospital of Istanbul University (I.U.) in Turkey and the Mammographic Image Analysis Society (MIAS). The results demonstrate that the proposed scheme LSRG-SWT achieves 96% and 93.59% accuracy in mass/non-mass classification (1st component) and benign/malignant classification (2nd component) respectively when using the I.U. database with k-fold cross validation. The system achieves 94% and 91.67% accuracy in mass/non-mass classification and benign/malignant classification respectively when using the I.U. database as a training set and the MIAS database as a test set with external validation.

  12. Seeing effects on occultation curves.

    NASA Technical Reports Server (NTRS)

    Young, A. T.

    1971-01-01

    Evaluation of seeing effects on the light curve of a stellar occultation by the moon. Some theoretical studies of Fried (1966) and Hulett (1967) on the linear size of the downward-looking seeing disk are cited, showing that the seeing blur amounts to a few centimeters for a star in the zenith and that the linear blur must grow approximately as (sec z) to the 3/2 power. For most observations the seeing blur will not exceed 8 to 10 cm. The limitation on angular resolution imposed by this seeing effect is calculated.

  13. Enhancement of Mammographic Density Measures in Breast Cancer Risk Prediction

    PubMed Central

    Cheddad, Abbas; Czene, Kamila; Shepherd, John A.; Li, Jingmei; Hall, Per; Humphreys, Keith

    2016-01-01

    Background Mammographic density is a strong risk factor for breast cancer. Methods We present a novel approach to enhance area density measures that takes advantage of the relative density of the pectoral muscle that appears in lateral mammographic views. We hypothesized that the grey scale of film mammograms is normalized to volume breast density but not pectoral density and thus pectoral density becomes an independent marker of volumetric density. Results From analysis of data from a Swedish case–control study (1,286 breast cancer cases and 1,391 control subjects, ages 50–75 years), we found that the mean intensity of the pectoral muscle (MIP) was highly associated with breast cancer risk [per SD: OR = 0.82; 95% confidence interval (CI), 0.75–0.88; P = 6 × 10−7] after adjusting for a validated computer-assisted measure of percent density (PD), Cumulus. The area under curve (AUC) changed from 0.600 to 0.618 due to using PD with the pectoral muscle as reference instead of a standard area-based PD measure. We showed that MIP is associated with a genetic variant known to be associated with mammographic density and breast cancer risk, rs10995190, in a subset of women with genetic data. We further replicated the association between MIP and rs10995190 in an additional cohort of 2,655 breast cancer cases (combined P = 0.0002). Conclusions MIP is a marker of volumetric density that can be used to complement area PD in mammographic density studies and breast cancer risk assessment. Impact Inclusion of MIP in risk models should be considered for studies using area PD from analog films. PMID:24722754

  14. PRONET services for distance learning in mammographic image processing.

    PubMed

    Costaridou, L; Panayiotakis, G; Efstratiou, C; Sakellaropoulos, P; Cavouras, D; Kalogeropoulou, C; Varaki, K; Giannakou, L; Dimopoulos, J

    1997-01-01

    The potential of telematics services is investigated with respect to learning needs of medical physicists and biomedical engineers. Telematics services are integrated into a system, the PRONET, which evolves around multimedia computer based courses and distance tutoring support. In addition, information database access and special interest group support are offered. System architecture is based on a component integration approach. The services are delivered in three modes: LAN, ISDN and Internet. Mammographic image processing is selected as an example content area. PMID:10179585

  15. Evaluation of Computer-aided Diagnosis on a Large Clinical Full-Field Digital Mammographic Dataset

    PubMed Central

    Li, Hui; Giger, Maryellen L.; Yuan, Yading; Chen, Weijie; Horsch, Karla; Lan, Li; Jamieson, Andrew R.; Sennett, Charlene A.; Jansen, Sanaz A.

    2008-01-01

    Rationale and Objectives: To convert and optimize our previously developed computerized analysis methods for use with images from full-field digital mammography (FFDM) for breast mass classification in order to aid in the diagnosis of breast cancer. Materials and Methods: An institutional review board approved protocol was obtained, with waiver of consent for retrospective use of mammograms and pathology data. Seven hundreds and thirty-nine full-field digital mammographic images, which contained 287 biopsy-proven breast mass lesions, of which 148 lesions were malignant and 139 lesions were benign, were retrospectively collected. Lesion margins were delineated by an expert breast radiologist and were used as the truth for lesion-segmentation evaluation. Our computerized image analysis method consisted of several steps: 1) identified lesions were automatically extracted from the parenchymal background using computerized segmentation methods; 2) a set of image characteristics (mathematical descriptors) were automatically extracted from image data of the lesions and surrounding tissues; and 3) selected features were merged into an estimate of the probability of malignancy using a Bayesian artificial neural network classifier. Performance of the analyses was evaluated at various stages of the conversion using receiver operating characteristic (ROC) analysis. Results: An AUC value of 0.81 was obtained in the task of distinguishing between malignant and benign mass lesions in a round-robin by case evaluation on the entire FFDM dataset. We failed to show a statistically significant difference (P value=0.83) as compared with results from our previous study in which the computerized classification was performed on digitized screen-film mammograms (SFMD). Conclusion: Our computerized analysis methods developed on digitized screen-film mammography can be converted for use with FFDM. Results show that the computerized analysis methods for the diagnosis of breast mass lesions on

  16. Mammographic images segmentation based on chaotic map clustering algorithm

    PubMed Central

    2014-01-01

    Background This work investigates the applicability of a novel clustering approach to the segmentation of mammographic digital images. The chaotic map clustering algorithm is used to group together similar subsets of image pixels resulting in a medically meaningful partition of the mammography. Methods The image is divided into pixels subsets characterized by a set of conveniently chosen features and each of the corresponding points in the feature space is associated to a map. A mutual coupling strength between the maps depending on the associated distance between feature space points is subsequently introduced. On the system of maps, the simulated evolution through chaotic dynamics leads to its natural partitioning, which corresponds to a particular segmentation scheme of the initial mammographic image. Results The system provides a high recognition rate for small mass lesions (about 94% correctly segmented inside the breast) and the reproduction of the shape of regions with denser micro-calcifications in about 2/3 of the cases, while being less effective on identification of larger mass lesions. Conclusions We can summarize our analysis by asserting that due to the particularities of the mammographic images, the chaotic map clustering algorithm should not be used as the sole method of segmentation. It is rather the joint use of this method along with other segmentation techniques that could be successfully used for increasing the segmentation performance and for providing extra information for the subsequent analysis stages such as the classification of the segmented ROI. PMID:24666766

  17. Relationship between breast sound speed and mammographic percent density

    NASA Astrophysics Data System (ADS)

    Sak, Mark; Duric, Nebojsa; Boyd, Norman; Littrup, Peter; Myc, Lukasz; Faiz, Muhammad; Li, Cuiping; Bey-Knight, Lisa

    2011-03-01

    Despite some shortcomings, mammography is currently the standard of care for breast cancer screening and diagnosis. However, breast ultrasound tomography is a rapidly developing imaging modality that has the potential to overcome the drawbacks of mammography. It is known that women with high breast densities have a greater risk of developing breast cancer. Measuring breast density is accomplished through the use of mammographic percent density, defined as the ratio of fibroglandular to total breast area. Using an ultrasound tomography (UST) prototype, we created sound speed images of the patient's breast, motivated by the fact that sound speed in a tissue is proportional to the density of the tissue. The purpose of this work is to compare the acoustic performance of the UST system with the measurement of mammographic percent density. A cohort of 251 patients was studied using both imaging modalities and the results suggest that the volume averaged breast sound speed is significantly related to mammographic percent density. The Spearman correlation coefficient was found to be 0.73 for the 175 film mammograms and 0.69 for the 76 digital mammograms obtained. Since sound speed measurements do not require ionizing radiation or physical compression, they have the potential to form the basis of a safe, more accurate surrogate marker of breast density.

  18. Early detection of occult atrial fibrillation and stroke prevention.

    PubMed

    Keach, Joseph Walker; Bradley, Steven M; Turakhia, Mintu P; Maddox, Thomas M

    2015-07-01

    Atrial fibrillation (AF) is a very common arrhythmia and significantly increases stroke risk. This risk can be mitigated with oral anticoagulation, but AF is often asymptomatic, or occult, preventing timely detection and treatment. Accordingly, occult AF may cause stroke before it is clinically diagnosed. Currently, guidelines for the early detection and treatment of occult AF are limited. This review addresses recent advancements in occult AF detection methods, identification of populations at high risk for occult AF, the treatment of occult AF with oral anticoagulation, as well as ongoing trials that may answer critically important questions regarding occult AF screening.

  19. The Approach to Occult Gastrointestinal Bleed.

    PubMed

    Naut, Edgar R

    2016-09-01

    Occult gastrointestinal bleeding is not visible and may present with a positive fecal occult blood test or iron deficiency anemia. Obscure bleeding can be overt or occult, with no source identified despite an appropriate diagnostic workup. A stepwise approach to this evaluation after negative upper and lower endoscopy has been shown to be cost effective. This includes repeat endoscopies if warranted, followed by video capsule endoscopy (VCE) if no obstruction is present. If the VCE is positive then specific endoscopic intervention may be possible. If negative, patients may undergo either repeat testing or watchful waiting with iron supplements.

  20. Stellar Occultation Studies of the Solar System

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    1998-01-01

    Earth-based observations of stellar occultations provide extremely high spatial resolution for bodies in the outer solar system, about 10,000 times better than that of traditional imaging observations. Stellar occultation data can be used to establish the structure of atmospheres and rings of solar system bodies at high spatial resolution. Airborne occultation observations are particularly effective, since the controlled mobility of the observing platform allows the observer to fly within the optimum part of the occultation shadow for most events that are visible from Earth. Airborne observations are carried out above any clouds and are nearly free of scintillation noise from the Earth's atmosphere. KAO occultation observations resulted in the first detection of gravity waves in the Martian atmosphere, discovery of the Uranian rings, the first detection of Pluto's atmosphere, the first Earth-based investigations of Triton's atmosphere, and the discovery of narrow jets from Chiron's nucleus. The first SOFIA occultation opportunity will be an investigation of Pluto's atmospheric structure in November, 2002, and will resolve a problem that has lingered since the KAO discovery observation fourteen years earlier. We plan to continue our successful airborne occultation program with the greatly enhanced capability provided by SOFIA. We propose here to replace our KAO occultation photometer with one having twice the throughput, half the noise, a somewhat wider wavelength range, four times the field of view, and ten times the frame rate to optimize its performance and to capitalize on the larger collecting area offered by SOFIA. It will also allow for simultaneous visible and IR occultation observations, greatly enriching the results that we can obtain from occultations. We call this new imaging occultation photometer HOPI (High-speed Occultation Photometer and Imager). HOPI will provide a signal-to-noise ratio two to four times that of our present photometer for a given

  1. Issues with external occultation of a coronagraph

    NASA Astrophysics Data System (ADS)

    Bayanna, A. Raja; Mathew, Shibu K.; Sankarasubramanian, K.; Venkatakrishnan, P.; Singh, J.; Prasad, B. R.

    2011-04-01

    This paper addresses some of the issues related to externally occulted solar coronagraph; vignetting and achievable resolution due to an external occulter. The analytical expression by Evans (J Opt Soc Am 38:1083-1085, 1948) is used to perform the initial calculations. An expression for the vignetting for a given external occulter and field angle is derived. The values obtained with the derived expression are verified with those obtained by ZEMAX an Optical design software. The degradation in angular resolution of the system due to vignetting is also presented and an empirical relation to calculate the normalized resolution for a given amount of vignetting is obtained.

  2. Mammographycally occult high grade ductal carcinoma in situ (DCIS) as second primary breast cancer, detected with MRI: a case report

    PubMed Central

    Zebic-Sinkovec, Marta; Kadivec, Maksimiljan; Podobnik, Gasper; Skof, Erik; Snoj, Marko

    2010-01-01

    Background Contralateral breast cancer (CLB) is the most common second primary breast cancer in patients diagnosed with breast cancer. The majority of patients harbouring CLB tumours develop the invasive disease. Almost all invasive carcinomas are believed to begin as ductal carcinoma in situ (DCIS) lesions. The sensitivity of MRI for DCIS is much higher than that of mammography. Case report We report the case of a woman who was treated with breast conserving therapy 10 years ago. At that time the invasive medullary carcinoma was diagnosed in the left breast. Ten years later mammographically occult DCIS was diagnosed with MRI-guided core biopsy in contralateral breast. Conclusions There might be a potential role of MRI screening as part of an annual follow-up for patients diagnosed with breast cancer. PMID:22933920

  3. Classification of mammographic lesion based in Completed Local Binary Pattern and using multiresolution representation

    NASA Astrophysics Data System (ADS)

    Duarte, Y. A. S.; Nascimento, M. Z.; Oliveira, D. L. L.

    2014-03-01

    This paper presents a comparison of two methods for features extraction of mammograms based in completed local binary pattern (CLBP) and wavelet transform. In first part, CLBP was applied in digitized mammograms. In second part, we applied CLBP in the sub-bands obtained from the wavelet multi-resolution representation of the mammographies. In this study, we evaluated the CLBP in the image in the spatial domain and in the sub-bands obtained with wavelet transform. Then, the statistical technique of variance analysis (ANOVA) was used to reduce the number of features. Finally, the classifier Support Vector Machine (SVM) was applied in the samples. The proposed methods were tested on 720 mammographies which 240 was diagnosed as normal samples, 240 as benign lesion and 240 as malign lesion. The images were obtained randomly of the Digital Database for Screening Mammography (DDSM). The system effectiveness was evaluated using the area under the ROC curve (AUC). The experiments demonstrate that the textural feature extraction of the multi-resolution representation was more relevant with value of AUC=1.0. In our experiments, CLBP in the spatial domain resulted in value of AUC=0.89. The proposed method demonstrated promising results in the classification of different classes of mammographic lesions.

  4. Digital mammographic tumor classification using transfer learning from deep convolutional neural networks.

    PubMed

    Huynh, Benjamin Q; Li, Hui; Giger, Maryellen L

    2016-07-01

    Convolutional neural networks (CNNs) show potential for computer-aided diagnosis (CADx) by learning features directly from the image data instead of using analytically extracted features. However, CNNs are difficult to train from scratch for medical images due to small sample sizes and variations in tumor presentations. Instead, transfer learning can be used to extract tumor information from medical images via CNNs originally pretrained for nonmedical tasks, alleviating the need for large datasets. Our database includes 219 breast lesions (607 full-field digital mammographic images). We compared support vector machine classifiers based on the CNN-extracted image features and our prior computer-extracted tumor features in the task of distinguishing between benign and malignant breast lesions. Five-fold cross validation (by lesion) was conducted with the area under the receiver operating characteristic (ROC) curve as the performance metric. Results show that classifiers based on CNN-extracted features (with transfer learning) perform comparably to those using analytically extracted features [area under the ROC curve [Formula: see text

  5. Finding corresponding regions of interest in mediolateral oblique and craniocaudal mammographic views

    SciTech Connect

    Engeland, Saskia van; Timp, Sheila; Karssemeijer, Nico

    2006-09-15

    In this paper we present a method to link potentially suspicious mass regions detected by a Computer-Aided Detection (CAD) scheme in mediolateral oblique (MLO) and craniocaudal (CC) mammographic views of the breast. For all possible combinations of mass candidate regions, a number of features are determined. These features include the difference in the radial distance from the candidate regions to the nipple, the gray scale correlation between both regions, and the mass likelihood of the regions determined by the single view CAD scheme. Linear Discriminant Analysis (LDA) is used to discriminate between correct and incorrect links. The method was tested on a set of 412 cancer cases. In each case a malignant mass, architectural distortion, or asymmetry was annotated. In 92% of these cases the candidate mass detections by CAD included the cancer regions in both views. It was found that in 82% of the cases a correct link between the true positive regions in both views could be established by our method. Possible applications of the method may be found in multiple view analysis to improve CAD results, and for the presentation of CAD results to the radiologist on a mammography workstation.

  6. Reflective Occultation Mask for Evaluation of Occulter Designs for Planet Finding

    NASA Technical Reports Server (NTRS)

    Hagopian, John; Lyon, Richard; Shiri, Shahram; Roman, Patrick

    2011-01-01

    Advanced formation flying occulter designs utilize a large occulter mask flying in formation with an imaging telescope to block and null starlight to allow imaging of faint planets in exosolar systems. A paper describes the utilization of subscale reflective occultation masks to evaluate formation flying occulter designs. The use of a reflective mask allows mounting of the occulter by conventional means and simplifies the test configuration. The innovation alters the test set-up to allow mounting of the mask using standard techniques to eliminate the problems associated with a standard configuration. The modified configuration uses a reflective set-up whereby the star simulator reflects off of a reflective occulting mask and into an evaluation telescope. Since the mask is sized to capture all rays required for the imaging test, it can be mounted directly to a supporting fixture without interfering with the beam. Functionally, the reflective occultation mask reflects light from the star simulator instead of transmitting it, with a highly absorptive carbon nanotube layer simulating the occulter blocking mask. A subscale telescope images the star source and companion dim source that represents a planet. The primary advantage of this is that the occulter can be mounted conventionally instead of using diffractive wires or magnetic levitation.

  7. Study of the technique of stellar occultation

    NASA Technical Reports Server (NTRS)

    Hays, P. B.; Graves, M. E.; Roble, R. G.; Shah, A. N.

    1973-01-01

    The results are reported of a study of the stellar occultation technique for measuring the composition of the atmosphere. The intensity of starlight was monitored during the occultation using the Wisconsin stellar ultraviolet photometers aboard the Orbiting Astronomical Observatory (OAO-A2). A schematic diagram of an occultation is shown where the change in intensity at a given wavelength is illustrated. The vertical projection of the attenuation region is typically 60 km deep for molecular oxygen and 30 km deep for ozone. Intensity profiles obtained during various occultations were analyzed by first determining the tangential columm density of the absorbing gases, and then Abel inverting the column densities to obtain the number density profile. Errors are associated with each step in the inversion scheme and have been considered as an integral part of this study.

  8. Triton stellar occultation candidates: 1995-1999

    NASA Technical Reports Server (NTRS)

    Mcdonald, S. W.; Elliot, J. L.

    1995-01-01

    We have completed a search for candidates for stellar occultations by Triton over the years 1995-1999. CCd strip scan images provided star positions in the relevant sky area to a depth of about 17.5 R magnitude. Over this time period, we find that Triton passes within 1.0 arcsec of 75 stars. Appulses with geocentric minimum separations of less than 0.35 arcsec will result in stellar occultations, but further astrometry and photometry is necessary to refine individual predictions for identification of actual occultations. Finder charts are included to aid in further studies and prediction refinement. The two most promising potential occultations, Tr176 and Tr180, occur in 1997.

  9. McDonald's and the Occult.

    ERIC Educational Resources Information Center

    Singer, Barry

    1979-01-01

    Discusses "occult" and "paranormal" literature which is often mistaken for nonfiction. Suggests that most publishers are unwilling to publish scientific perspectives on the paranormal because such writings would be unmarketable. Journal availability: see SO 507 190. (KC)

  10. Diagnostic Workup and Costs of a Single Supplemental Molecular Breast Imaging Screen of Mammographically Dense Breasts

    PubMed Central

    Hruska, Carrie B.; Conners, Amy Lynn; Jones, Katie N.; O’Connor, Michael K.; Moriarty, James P.; Boughey, Judy C.; Rhodes, Deborah J.

    2016-01-01

    OBJECTIVE The purpose of this study was to examine additional diagnostic workup and costs generated by addition of a single molecular breast imaging (MBI) examination to screening mammography for women with dense breasts. SUBJECTS AND METHODS Women with mammographically dense breasts presenting for screening mammography underwent adjunct MBI performed with 300 MBq 99mTc-sestamibi and a direct-conversion cadmium-zinc-telluride dual-head gamma camera. All subsequent imaging tests and biopsies were tracked for a minimum of 1 year. The positive predictive value of biopsies performed (PPV3), benign biopsy rate, cost per patient screened, and cost per cancer detected were determined. RESULTS A total of 1651 women enrolled in the study. Among the 1585 participants with complete reference standard, screening mammography alone prompted diagnostic workup of 175 (11.0%) patients and biopsy of 20 (1.3%) and yielded five malignancies (PPV3, 25%). Results of combined screening mammography plus MBI prompted diagnostic workup of 279 patients (17.6%) and biopsy of 67 (4.2%) and yielded 19 malignancies (PPV3, 28.4%). The benign biopsy rates were 0.9% (15 of 1585) for screening mammography alone and 3.0% (48 of 1585) for the combination (p < 0.001). The addition of MBI increased the cost per patient screened from $176 for mammography alone to $571 for the combination. However, cost per cancer detected was lower for the combination ($47,597) than for mammography alone ($55,851). CONCLUSION The addition of MBI to screening mammography of women with dense breasts increased the overall costs and benign biopsy rate but also increased the cancer detection rate, which resulted in a lower cost per cancer detected than with screening mammography alone. PMID:26001247

  11. Grid-enabled mammographic auditing and training system

    NASA Astrophysics Data System (ADS)

    Yap, M. H.; Gale, A. G.

    2008-03-01

    Effective use of new technologies to support healthcare initiatives is important and current research is moving towards implementing secure grid-enabled healthcare provision. In the UK, a large-scale collaborative research project (GIMI: Generic Infrastructures for Medical Informatics), which is concerned with the development of a secure IT infrastructure to support very widespread medical research across the country, is underway. In the UK, there are some 109 breast screening centers and a growing number of individuals (circa 650) nationally performing approximately 1.5 million screening examinations per year. At the same, there is a serious, and ongoing, national workforce issue in screening which has seen a loss of consultant mammographers and a growth in specially trained technologists and other non-radiologists. Thus there is a need to offer effective and efficient mammographic training so as to maintain high levels of screening skills. Consequently, a grid based system has been proposed which has the benefit of offering very large volumes of training cases that the mammographers can access anytime and anywhere. A database, spread geographically across three university systems, of screening cases is used as a test set of known cases. The GIMI mammography training system first audits these cases to ensure that they are appropriately described and annotated. Subsequently, the cases are utilized for training in a grid-based system which has been developed. This paper briefly reviews the background to the project and then details the ongoing research. In conclusion, we discuss the contributions, limitations, and future plans of such a grid based approach.

  12. Mammographic density measurements are not affected by mammography system

    PubMed Central

    Damases, Christine N.; Brennan, Patrick C.; McEntee, Mark F.

    2015-01-01

    Abstract. Mammographic density (MD) is a significant risk factor for breast cancer and has been shown to reduce the sensitivity of mammography screening. Knowledge of a woman’s density can be used to predict her risk of developing breast cancer and personalize her imaging pathway. However, measurement of breast density has proven to be troublesome with wide variations in density recorded using radiologists’ visual Breast Imaging Reporting and Data System (BIRADS). Several automated methods for assessing breast density have been proposed, each with their own source of measurement error. The use of differing mammographic imaging systems further complicates MD measurement, especially for the same women imaged over time. The purpose of this study was to investigate whether having a mammogram on differing manufacturer’s equipment affects a woman’s MD measurement. Raw mammographic images were acquired on two mammography imaging systems (General Electric and Hologic) one year apart and processed using VolparaDensity™ to obtain the Volpara Density Grade (VDG) and average volumetric breast density percentage (AvBD%). Visual BIRADS scores were also obtained from 20 expert readers. BIRADS scores for both systems showed strong positive correlation (ρ=0.904; p<0.001), while the VDG (ρ=0.978; p<0.001) and AvBD% (ρ=0.973; p<0.001) showed stronger positive correlations. Substantial agreement was shown between the systems for BIRADS (κ=0.692; p<0.001), however, the systems demonstrated an almost perfect agreement for VDG (κ=0.933; p<0.001). PMID:26158085

  13. Angular dependence of mammographic dosimeters in digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Bradley, Lena R.; Carton, Ann-Katherine; Maidment, Andrew D. A.

    2010-04-01

    Digital Breast Tomosynthesis (DBT) is an emerging imaging modality that combines tomography with conventional digital mammography. In developing DBT dosimetry, a direct application of mammographic dosimetry has appeal. However, DBT introduces rotation of the x-ray tube relative to the dosimeter, thus raising questions about the angular dependence of mammographic dosimeters. To measure this dependence, two ionization chambers, two solid-stated detectors, and one photodiode were rotated relative to an incident Mo/Mo x-ray beam. In this isocentric DBT simulation, the signal of each dosimeter was studied over an angular range of 180° for tube voltages of 26 to 34 kV. One ionization chamber was then modeled numerically to study the response to various monoenergetic beams. The results show that all dosimeters underestimate dose to varying degrees; solid-state detectors show the greatest angular dependence while ionization chambers show the least. Correction factors were computed from the data for isocentric DBT images using projection angles up to +/-25° these factors ranged from 1.0014 to 1.1380. The magnitude of the angular dependence generally decreased with increasing energy, as shown with both the measured and modeled data. As a result, the error arising in measuring DBT dose with a mammographic dosimeter varies significantly; it cannot always be disregarded. The use of correction factors may be possible but is largely impractical, as they are specific to the dosimeter, x-ray beam, and DBT geometry. Instead, an angle-independent dosimeter may be more suitable for DBT.

  14. A new detection algorithm for microcalcification clusters in mammographic screening

    NASA Astrophysics Data System (ADS)

    Xie, Weiying; Ma, Yide; Li, Yunsong

    2015-05-01

    A novel approach for microcalcification clusters detection is proposed. At the first time, we make a short analysis of mammographic images with microcalcification lesions to confirm these lesions have much greater gray values than normal regions. After summarizing the specific feature of microcalcification clusters in mammographic screening, we make more focus on preprocessing step including eliminating the background, image enhancement and eliminating the pectoral muscle. In detail, Chan-Vese Model is used for eliminating background. Then, we do the application of combining morphology method and edge detection method. After the AND operation and Sobel filter, we use Hough Transform, it can be seen that the result have outperformed for eliminating the pectoral muscle which is approximately the gray of microcalcification. Additionally, the enhancement step is achieved by morphology. We make effort on mammographic image preprocessing to achieve lower computational complexity. As well known, it is difficult to robustly achieve mammograms analysis due to low contrast between normal and lesion tissues, there are also much noise in such images. After a serious preprocessing algorithm, a method based on blob detection is performed to microcalcification clusters according their specific features. The proposed algorithm has employed Laplace operator to improve Difference of Gaussians (DoG) function in terms of low contrast images. A preliminary evaluation of the proposed method performs on a known public database namely MIAS, rather than synthetic images. The comparison experiments and Cohen's kappa coefficients all demonstrate that our proposed approach can potentially obtain better microcalcification clusters detection results in terms of accuracy, sensitivity and specificity.

  15. Evaluation for Occult Fractures in Injured Children

    PubMed Central

    French, Benjamin; Song, Lihai; Feudtner, Chris

    2015-01-01

    OBJECTIVES: To examine variation across US hospitals in evaluation for occult fractures in (1) children <2 years old diagnosed with physical abuse and (2) infants <1 year old with injuries associated with a high likelihood of abuse and to identify factors associated with such variation. METHODS: We performed a retrospective study in children <2 years old with a diagnosis of physical abuse and in infants <1 year old with non-motor vehicle crash–related traumatic brain injury or femur fractures discharged from 366 hospitals in the Premier database from 2009 to 2013. We examined across-hospital variation and identified child- and hospital-level factors associated with evaluation for occult fractures. RESULTS: Evaluations for occult fractures were performed in 48% of the 2502 children with an abuse diagnosis, in 51% of the 1574 infants with traumatic brain injury, and in 53% of the 859 infants with femur fractures. Hospitals varied substantially with regard to their rates of evaluation for occult fractures in all 3 groups. Occult fracture evaluations were more likely to be performed at teaching hospitals than at nonteaching hospitals (all P < .001). The hospital-level annual volume of young, injured children was associated with the probability of occult fracture evaluation, such that hospitals treating more young, injured patients were more likely to evaluate for occult fractures (all P < .001). CONCLUSIONS: Substantial variation in evaluation for occult fractures among young children with a diagnosis of abuse or injuries associated with a high likelihood of abuse highlights opportunities for quality improvement in this vulnerable population. PMID:26169425

  16. Digital Breast Tomosynthesis versus Supplemental Diagnostic Mammographic Views for Evaluation of Noncalcified Breast Lesions

    PubMed Central

    Bandos, Andriy I.; Ganott, Marie A.; Sumkin, Jules H.; Kelly, Amy E.; Catullo, Victor J.; Rathfon, Grace Y.; Lu, Amy H.; Gur, David

    2013-01-01

    Purpose: To compare the diagnostic performance of breast tomosynthesis versus supplemental mammography views in classification of masses, distortions, and asymmetries. Materials and Methods: Eight radiologists who specialized in breast imaging retrospectively reviewed 217 consecutively accrued lesions by using protocols that were HIPAA compliant and institutional review board approved in 182 patients aged 31–60 years (mean, 50 years) who underwent diagnostic mammography and tomosynthesis. The lesions in the cohort included 33% (72 of 217) cancers and 67% (145 of 217) benign lesions. Eighty-four percent (182 of 217) of the lesions were masses, 11% (25 of 217) were asymmetries, and 5% (10 of 217) were distortions that were initially detected at clinical examination in 8% (17 of 217), at mammography in 80% (173 of 217), at ultrasonography (US) in 11% (25 of 217), or at magnetic resonance imaging in 1% (2 of 217). Histopathologic examination established truth in 191 lesions, US revealed a cyst in 12 lesions, and 14 lesions had a normal follow-up. Each lesion was interpreted once with tomosynthesis and once with supplemental mammographic views; both modes included the mediolateral oblique and craniocaudal views in a fully crossed and balanced design by using a five-category Breast Imaging Reporting and Data System (BI-RADS) assessment and a probability-of-malignancy score. Differences between modes were analyzed with a generalized linear mixed model for BI-RADS–based sensitivity and specificity and with modified Obuchowski-Rockette approach for probability-of-malignancy–based area under the receiver operating characteristic (ROC) curve. Results: Average probability-of-malignancy–based area under the ROC curve was 0.87 for tomosynthesis versus 0.83 for supplemental views (P < .001). With tomosynthesis, the false-positive rate decreased from 85% (989 of 1160) to 74% (864 of 1160) (P < .01) for cases that were rated BI-RADS category 3 or higher and from 57% (663 of

  17. Radio occultation measurements of the lunar ionosphere.

    NASA Astrophysics Data System (ADS)

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.; Maccaferri, G.; Cassaro, P.

    Radio occultation measurements by using interplanetary probes is a well known technique to obtain information on planetary atmospheres. To further understand the morphology of the lunar ionosphere we performed radio occultation experiments by using the radio sounding technique. This method mainly consists in the analisys of the effects produced on the radio wave transmitted from the spacecraft to the Earth when it crosses the atmosphere. The wave amplitude and phase undergo modifications that are correlated to the physical parameters - i.e. electron density - of the crossed medium. The first data set was obtained during the lunar occultations of the European probe SMART-1 shortly before impacting the lunar soil on September 3rd, 2006. During this experiment several radio occultation measurements of the signal transmitted by the spacecraft were performed in S and X band by using the 32 meters radiotelescopes (at Medicina and Noto) of the Istituto di Radioastronomia - Istituto Nazionale di Astrofisica. Further experiments were performed during lunar occultations of Saturn and Venus. On May 22nd and June 18th 2007 the Cassini spacecraft, orbiting Saturn, and the Venus Express spacecraft, orbiting Venus, respectively were occulted by the Moon. The variation of the Total Electron Content (TEC) measured by our instruments (˜ 1013 el/m2) on this occasion is in agreement with values of the electron number density acquired by in situ measuments of the US Apollo missions and the USSR Luna 19 and 22 probes.

  18. Transillumination of the occult submucous cleft palate.

    PubMed

    Caterson, E J; Tsai, David M; Cauley, Ryan; Dowdall, Jayme R; Tracy, Lauren E

    2014-11-01

    Occult submucous cleft palate is a congenital deformity characterized by deficient union of the muscles that normally cross the velum and aid in elevation of the soft palate. Despite this insufficient muscle coverage, occult submucous cleft palate by definition lacks clear external anatomic landmarks. This absence of anatomic signs makes diagnosis of occult submucous cleft less obvious, more dependent on ancillary tests, and potentially missed entirely. Current diagnostic methodologies are limited and often are unrevealing in the presurgical patient; however, a missed diagnosis of occult submucous cleft palate can result in velopharyngeal insufficiency and major functional impairment in patients after surgery on the oropharynx. By accurately and easily diagnosing occult submucous cleft palate, it is possible to defer or modify pharyngeal surgical intervention that may further impair velopharyngeal function in susceptible patients. In this report, we introduce transillumination of the soft palate using a transnasal or transoral flexible endoscope as an inexpensive and simple technique for identification of submucous cleft palate. The use of transillumination of an occult submucous cleft palate is illustrated in a patient case and is compared to other current diagnostic methodologies.

  19. Method of Modeling and Simulation of Shaped External Occulters

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G. (Inventor); Clampin, Mark (Inventor); Petrone, Peter, III (Inventor)

    2016-01-01

    The present invention relates to modeling an external occulter including: providing at least one processor executing program code to implement a simulation system, the program code including: providing an external occulter having a plurality of petals, the occulter being coupled to a telescope; and propagating light from the occulter to a telescope aperture of the telescope by scalar Fresnel propagation, by: obtaining an incident field strength at a predetermined wavelength at an occulter surface; obtaining a field propagation from the occulter to the telescope aperture using a Fresnel integral; modeling a celestial object at differing field angles by shifting a location of a shadow cast by the occulter on the telescope aperture; calculating an intensity of the occulter shadow on the telescope aperture; and applying a telescope aperture mask to a field of the occulter shadow, and propagating the light to a focal plane of the telescope via FFT techniques.

  20. Malignant adenolymphoma.

    PubMed

    Moosavi, H; Ryan, C; Schwartz, S; Donnelly, J A

    1980-01-01

    Adenolymphoma (Warthin's tumor) is a well studied benign tumor of the salivary gland. Malignant transformation of such a tumor is rare and not well documented in the literature. The light microscopic and ultrastructural features of an undifferentiated carcinoma arising in an adenolymphoma in the parotid gland of a middle aged male are described, and the relevant literature is reviewed. Similarities between the benign adenolymphoma and the undifferentiated malignant tumor, such as the presence of interstitial lymphoplasmacytic cell infiltrates, dark and light epithelial cells, similar cytoplasmic organelles, and nuclear morphology, suggest a malignant transformation of a previously existing benign adenolymphoma.

  1. External validation of a publicly available computer assisted diagnostic tool for mammographic mass lesions with two high prevalence research datasets

    PubMed Central

    Benndorf, Matthias; Burnside, Elizabeth S.; Herda, Christoph; Langer, Mathias; Kotter, Elmar

    2015-01-01

    Purpose: Lesions detected at mammography are described with a highly standardized terminology: the breast imaging-reporting and data system (BI-RADS) lexicon. Up to now, no validated semantic computer assisted classification algorithm exists to interactively link combinations of morphological descriptors from the lexicon to a probabilistic risk estimate of malignancy. The authors therefore aim at the external validation of the mammographic mass diagnosis (MMassDx) algorithm. A classification algorithm like MMassDx must perform well in a variety of clinical circumstances and in datasets that were not used to generate the algorithm in order to ultimately become accepted in clinical routine. Methods: The MMassDx algorithm uses a naïve Bayes network and calculates post-test probabilities of malignancy based on two distinct sets of variables, (a) BI-RADS descriptors and age (“descriptor model”) and (b) BI-RADS descriptors, age, and BI-RADS assessment categories (“inclusive model”). The authors evaluate both the MMassDx (descriptor) and MMassDx (inclusive) models using two large publicly available datasets of mammographic mass lesions: the digital database for screening mammography (DDSM) dataset, which contains two subsets from the same examinations—a medio–lateral oblique (MLO) view and cranio–caudal (CC) view dataset—and the mammographic mass (MM) dataset. The DDSM contains 1220 mass lesions and the MM dataset contains 961 mass lesions. The authors evaluate discriminative performance using area under the receiver-operating-characteristic curve (AUC) and compare this to the BI-RADS assessment categories alone (i.e., the clinical performance) using the DeLong method. The authors also evaluate whether assigned probabilistic risk estimates reflect the lesions’ true risk of malignancy using calibration curves. Results: The authors demonstrate that the MMassDx algorithms show good discriminatory performance. AUC for the MMassDx (descriptor) model in the

  2. Evaluation of four mammographic density measures on HRT data

    NASA Astrophysics Data System (ADS)

    Raundahl, Jakob; Loog, Marco; Pettersen, Paola; Nielsen, Mads

    2007-03-01

    Numerous studies have investigated the relation between mammographic density and breast cancer risk. These studies indicate that women with dense breasts have a four to six fold risk increase. There is currently no gold standard for automatic assessment of mammographic density. In previous work two different automated methods for measuring the effect of HRT w.r.t. changes in breast density have been presented. One is a percentage density based on an adaptive global threshold, and the other is an intensity invariant measure, which provides structural information orthogonal to intensity-based methods. In this article we investigate the ability to detect density changes induced by HRT for these measures and compare to a radiologist's BI-RADS rating and interactive threshold percentage density. In the experiments, two sets of mammograms of 80 patients from a double blind, placebo controlled HRT experiment are used. The p-values for the statistical significance of the separation of density means, for the HRT group and the placebo group at end of study, are 0.2, 0.1, 0.02 and 0.02 for the automatic threshold, BI-RADS, the stripyness and the interactive threshold respectively.

  3. Mammographic artifacts on full-field digital mammography.

    PubMed

    Choi, Jae Jeong; Kim, Sung Hun; Kang, Bong Joo; Choi, Byung Gil; Song, ByungJoo; Jung, Haijo

    2014-04-01

    This study investigates the incidence of full-field digital mammographic (FFDM) artifacts with three systems at two institutions and compares the artifacts between two detector types and two grid types. A total of 4,440 direct and 4,142 indirect FFDM images were reviewed by two radiologists, and artifacts were classified as patient related, hardware related, and software processing. The overall incidence of FFDM artifacts was 3.4% (292/8,582). Patient related artifacts (motion artifacts and skin line artifacts) were the most commonly detected types (1.7%). Underexposure among hardware related artifacts and high-density artifacts among software processing artifacts also were common (0.7 and 0.5%, respectively). These artifacts, specific to digital mammography, were more common with the direct detector type and the crossed air grid type than with the indirect type and linear grid type (p < 0.05). The most common mammographic artifacts on FFDM were patient related, which might be controlled by the instruction of a patient and technologist. Underexposure and high-density artifacts were more common with direct detector and crossed air type of grid.

  4. Computerized quantitative evaluation of mammographic accreditation phantom images

    SciTech Connect

    Lee, Yongbum; Tsai, Du-Yih; Shinohara, Norimitsu

    2010-12-15

    Purpose: The objective was to develop and investigate an automated scoring scheme of the American College of Radiology (ACR) mammographic accreditation phantom (RMI 156, Middleton, WI) images. Methods: The developed method consisted of background subtraction, determination of region of interest, classification of fiber and mass objects by Mahalanobis distance, detection of specks by template matching, and rule-based scoring. Fifty-one phantom images were collected from 51 facilities for this study (one facility provided one image). A medical physicist and two radiologic technologists also scored the images. The human and computerized scores were compared. Results: In terms of meeting the ACR's criteria, the accuracies of the developed method for computerized evaluation of fiber, mass, and speck were 90%, 80%, and 98%, respectively. Contingency table analysis revealed significant association between observer and computer scores for microcalcifications (p<5%) but not for masses and fibers. Conclusions: The developed method may achieve a stable assessment of visibility for test objects in mammographic accreditation phantom image in whether the phantom image meets the ACR's criteria in the evaluation test, although there is room left for improvement in the approach for fiber and mass objects.

  5. High mammographic density in women of Ashkenazi Jewish descent

    PubMed Central

    2013-01-01

    Introduction Percent mammographic density (PMD) adjusted for age and body mass index is one of the strongest risk factors for breast cancer and is known to be approximately 60% heritable. Here we report a finding of an association between genetic ancestry and adjusted PMD. Methods We selected self-identified Caucasian women in the California Pacific Medical Center Research Institute Cohort whose screening mammograms placed them in the top or bottom quintiles of age-adjusted and body mass index-adjusted PMD. Our final dataset included 474 women with the highest adjusted PMD and 469 with the lowest genotyped on the Illumina 1 M platform. Principal component analysis (PCA) and identity-by-descent analyses allowed us to infer the women's genetic ancestry and correlate it with adjusted PMD. Results Women of Ashkenazi Jewish ancestry, as defined by the first principal component of PCA and identity-by-descent analyses, represented approximately 15% of the sample. Ashkenazi Jewish ancestry, defined by the first principal component of PCA, was associated with higher adjusted PMD (P = 0.004). Using multivariate regression to adjust for epidemiologic factors associated with PMD, including age at parity and use of postmenopausal hormone therapy, did not attenuate the association. Conclusions Women of Ashkenazi Jewish ancestry, based on genetic analysis, are more likely to have high age-adjusted and body mass index-adjusted PMD. Ashkenazi Jews may have a unique set of genetic variants or environmental risk factors that increase mammographic density. PMID:23668689

  6. Adolescent intake of animal fat and red meat in relation to premenopausal mammographic density.

    PubMed

    Bertrand, Kimberly A; Burian, Rosemarie A; Eliassen, A Heather; Willett, Walter C; Tamimi, Rulla M

    2016-01-01

    Adolescence is hypothesized to be a time period of particular susceptibility to breast cancer risk factors. Red meat and fat intake during high school was positively associated with risk of breast cancer among premenopausal women in the Nurses' Health Study II (NHSII). High mammographic density is a strong predictor of breast cancer risk but there is limited research on dietary factors associated with breast density. To test the hypothesis that high intake of animal fat or red meat during adolescence is associated with mammographic density, we analyzed data from premenopausal women in the NHSII. Participants recalled adolescent diet on a high school food frequency questionnaire. We assessed absolute and percent mammographic density on digitized analog film mammograms for 687 premenopausal women with no history of cancer. We used generalized linear regression to quantify associations of adolescent animal fat and red meat intake with mammographic density, adjusting for age, body mass index, and other predictors of mammographic density. Adolescent animal fat intake was significantly positively associated with premenopausal mammographic density, with a mean percent density of 39.2 % in the lowest quartile of adolescent animal fat intake versus 43.1 % in the highest quartile (p trend: 0.03). A non-significant positive association was also observed for adolescent red meat intake (p trend: 0.14). These findings suggest that higher adolescent animal fat intake is weakly associated with percent mammographic density in premenopausal women.

  7. Malignant hyperthermia.

    PubMed

    Brockhouse, R T

    1979-04-01

    A case has been presented that illustrates successful managment of a patient with suspected malignant hyperthermia. The causes of this disorder are uncertain. If screening procedures identify a patient as susceptible to this disorder, careful planning in the preoperative stage is indicated. Preparedness during the operative procedure for any emergency is mandatory. Early and effective treatment seems to be the only method of preventing mortality with patients experiencing malignant hyperthermia. PMID:285135

  8. Malignant oncocytoma.

    PubMed

    Laurian, N; Zohar, Y; Kende, L

    1977-09-01

    A case of malignant oncocytoma of the parotid gland in a 32-year-old male is presented. Ten months after parotidectomy an undifferentiated carcinoma, in which oncocytes still could be recognized, developed in the operated area. According to the literature available to us, this is the second reported case in which malignant transformation in a benign oncocytoma of the salivary gland has been observed.

  9. The 22 May 2011 Pluto occultation - observed

    NASA Astrophysics Data System (ADS)

    Pasachoff, J. M.; Souza, S. P.; Babcock, B. A.; Pandey, S.; Hosek, M. W.; Person, M. J.; Gulbis, A. A. S.; Bosh, A. S.; Zuluaga, C. A.; Ryan, E. V.; Ryan, W. H.; Briggs, J. W.; Winkler, P. F.; Hoette, V.; Haislip, J.

    2011-10-01

    Based on a prediction from MIT with astrometric observations from the USNO and Lowell Observatory, we observed the 22 May 2011 UT 06:22 occultation of a star by Pluto (www.stellaroccultations.info and occult.mit.edu), predicted time. The star occulted was UCAC2 magnitude 15.3, and the event's geocentric velocity was 18.2 km s-1. We used the 0.6-m telescope of Williams College's Hopkins Observatory in Williamstown, MA, and one of our Portable Occultation, Eclipse, and Transit System (POETS) CCD/GPS. The centerline of the predicted path was just above the north pole, with the southern limit passing through the U.S. mid-Atlantic, so telescopes in the northeast were potentially in the path, though at high air mass. An occultation of approximately 100 s was clearly detected after calibrating on a nearby comparison star (and barely visible on the CCD monitoring screen in real time), given the relatively cloudy and variable nature of the observing conditions. We used the observation to refine the prediction model that is crucial for the 23/27 June occultations of Pluto-Charon/Pluto-Hydra, respectively. Observations in clear conditions with the Magdalena Ridge Observatory's 2.4-m telescope in New Mexico and another of our POETS did not show an occultation to better than 1%. This nondetection provides a constraint for a Pluto atmospheric graze or the potential shift of the path of Charon sufficiently far north to that site from the predicted path in northernmost South America.

  10. Earth rotation derived from occultation records

    NASA Astrophysics Data System (ADS)

    Sôma, Mitsuru; Tanikawa, Kiyotaka

    2016-04-01

    We determined the values of the Earth's rotation parameter, ΔT = T T - UT, around AD 500 after confirming that the value of the tidal acceleration, dot{n}, of the lunar motion remained unchanged during the period between ancient times and the present. For determining of ΔT, we used contemporaneous occultations of planets by the Moon. In general, occultation records are not useful. However, there are some records that give us a stringent condition for the range of ΔT. Records of the lunar occultations in AD 503 and AD 513 are such examples. In order to assure the usefulness of this occultation data, we used contemporaneous annular and total solar eclipses, which have not been used in the preceding work. This is the first work in which the lunar occultation data have been used as primary data to determine the value of ΔT together with auxiliary contemporaneous annular and total solar eclipses. Our ΔT value is less than a smoothed value (Stephenson 1997) by at least 450 s. The result is consistent with our earlier results obtained from solar eclipses.

  11. General Information about Metastatic Squamous Neck Cancer with Occult Primary

    MedlinePlus

    ... with Occult Primary Treatment (PDQ®)–Patient Version General Information About Metastatic Squamous Neck Cancer with Occult Primary ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  12. [Occult hepatitis B virus infection and hepatocellular carcinoma].

    PubMed

    Lee, Jong Joon; Kwon, Oh Sang

    2013-09-01

    Many studies have suggested that occult HBV infection has a substantial clinical relevance to hepatocellular carcinoma (HCC). Occult HBV infection is an important risk factor for the development of cirrhosis and HCC in patients without HBsAg. As a matter of fact, occult HBV infection is one of the most common causes of crytogenic HCC in endemic areas of HBV. However, there still are controversial issues about the association between occult HBV infection and HCC according to the underlying liver disease. In alcoholic cirrhosis, occult HBV infection may exert synergistic effect on the development of HCC. However, there is insufficient evidence to relate occult HBV infection to hepatocarcinogenesis in non-alcoholic fatty liver disease. In cryptogenic HCC, occult HBV infection may play a direct role in the development of HCC. In order to elucidate the assocciation between occult HBV infection and HCC, underlying liver disease must be specified and larger number of cases must be included in future studies.

  13. Occult Breast Cancer: Scintimammography with High-Resolution Breast-specific Gamma Camera in Women at High Risk for Breast Cancer

    SciTech Connect

    Rachel F. Brem; Jocelyn A. Rapelyea; , Gilat Zisman; Kevin Mohtashemi; Joyce Raub; Christine B. Teal; Stan Majewski; Benjamin L. Welch

    2005-08-01

    To prospectively evaluate a high-resolution breast-specific gamma camera for depicting occult breast cancer in women at high risk for breast cancer but with normal mammographic and physical examination findings. MATERIALS AND METHODS: Institutional Review Board approval and informed consent were obtained. The study was HIPAA compliant. Ninety-four high-risk women (age range, 36-78 years; mean, 55 years) with normal mammographic (Breast Imaging Reporting and Data System [BI-RADS] 1 or 2) and physical examination findings were evaluated with scintimammography. After injection with 25-30 mCi (925-1110 MBq) of technetium 99m sestamibi, patients were imaged with a high-resolution small-field-of-view breast-specific gamma camera in craniocaudal and mediolateral oblique projections. Scintimammograms were prospectively classified according to focal radiotracer uptake as normal (score of 1), with no focal or diffuse uptake; benign (score of 2), with minimal patchy uptake; probably benign (score of 3), with scattered patchy uptake; probably abnormal (score of 4), with mild focal radiotracer uptake; and abnormal (score of 5), with marked focal radiotracer uptake. Mammographic breast density was categorized according to BI-RADS criteria. Patients with normal scintimammograms (scores of 1, 2, or 3) were followed up for 1 year with an annual mammogram, physical examination, and repeat scintimammography. Patients with abnormal scintimammograms (scores of 4 or 5) underwent ultrasonography (US), and those with focal hypoechoic lesions underwent biopsy. If no lesion was found during US, patients were followed up with scintimammography. Specific pathologic findings were compared with scintimammographic findings. RESULTS: Of 94 women, 78 (83%) had normal scintimammograms (score of 1, 2, or 3) at initial examination and 16 (17%) had abnormal scintimammograms (score of 4 or 5). Fourteen (88%) of the 16 patients had either benign findings at biopsy or no focal abnormality at US; in two

  14. Occult hepatitis B virus infection

    PubMed Central

    Kwak, Min-Sun; Kim, Yoon Jun

    2014-01-01

    Occult hepatitis B virus (HBV) infection (OBI) refers to the presence of HBV DNA in the absence of detectable hepatitis B surface antigen. Since OBI was first described in the late 1970s, there has been increasing interest in this topic. The prevalence of OBI varies according to the different endemicity of HBV infection, cohort characteristics, and sensitivity and specificity of the methods used for detection. Although the exact mechanism of OBI has not been proved, intra-hepatic persistence of viral covalently closed circular DNA under the host’s strong immune suppression of HBV replication and gene expression seems to be a cause. OBI has important clinical significance in several conditions. First, OBI can be transmitted through transfusion, organ transplantation including orthotopic liver transplantation, or hemodialysis. Donor screening before blood transfusion, prophylaxis for high-risk organ transplantation recipients, and dialysis-specific infection-control programs should be considered to reduce the risk of transmission. Second, OBI may reactivate and cause acute hepatitis in immunocompromised patients or those receiving chemotherapy. Close HBV DNA monitoring and timely antiviral treatment can prevent HBV reactivation and consequent clinical deterioration. Third, OBI may contribute to the progression of hepatic fibrosis in patients with chronic liver disease including hepatitis C. Finally, OBI seems to be a risk factor for hepatocellular carcinoma by its direct proto-oncogenic effect and by indirectly causing persistent hepatic inflammation and fibrosis. However, this needs further investigation. We review published reports in the literature to gain an overview of the status of OBI and emphasize the clinical importance of OBI. PMID:25544873

  15. Pleural malignancies.

    PubMed

    Vargas, F S; Teixeira, L R

    1996-07-01

    Carcinoma of the lung, metastatic breast carcinoma, and lymphoma are responsible for approximately 75% of all malignant pleural effusions. The presence of malignant cells in the pleural fluid or in the parietal pleura confirms the diagnosis. Recently, several authors have proposed the combination of morphometric procedures and quantitative analysis of nucleolar organizer regions stained by silver nitrate. Videothoracoscopy is recommended for patients suspected of having a malignant pleural effusion in whom the diagnosis is not established after two cytologic studies of the fluid and one needle biopsy. The standard treatment is the intrapleural instillation of a chemical agent to produce a pleurodesis. The recommended sclerosant is talc, a tetracycline derivative, or Corynebacterium parvum where it is available. When a patient is not an ideal candidate for chemical pleurodesis, the options include symptomatic treatment, serial thoracentesis, implantation of a pleuroperitoneal shunt, and pleurectomy. PMID:9363162

  16. Chiron stellar occultation candidates: 1993-1996

    NASA Technical Reports Server (NTRS)

    Bus, S. J.; Wasserman, L. H.; Elliot, J. L.

    1994-01-01

    A photographic search was conducted for stars that may be occulted by the unusual solar system object (2060) Chiron during the period from fall 1993 through summer 1996. 44 candidates were identified to a limiting V magnitude of 16, and for which the minimum appulse separation with Chiron is predicted to be less than 2.5 arcsec. The successful observation of a stellar occultation by Chiron would give a direct measure of its diameter (currently estimated to be between 60 and 300 km), and would help considerably in constraining Chiron's surface properties and volatile makeup. If at the time of the occultation, Chiron exhibits a significant coma, there is also the potential for measuring the optical-depth profile of the dust in its inner coma.

  17. Occult chemical deposition to a Maritime forest

    SciTech Connect

    Vong, R.J.; Kowalski, A.S.

    1996-12-31

    Studies of chemical fluxes from the atmosphere to vegetated surfaces have suggested that, along with conventional wet and dry processes, an additional chemical input occurs when wind-blown cloud droplets are directly intercepted by vegetation. This cloud water deposition process has been sometimes termed {open_quote}occult deposition{close_quote} because the water fluxes cannot ordinarily be observed using rain gauges. Such occult deposition of cloud water has rarely been measured directly, in part because of the complexity of the governing turbulent transfer process. However, reviews by the National Acidic Precipitation Assessment Program (NAPAP SoS/T-2,6) have suggested that the chemical flux to be forest decline in the eastern USA. This paper presents direct field measurements occult chemical fluxes to a silver fir forest located in complex terrain on the Olympic Peninsula near the coast of Washington State, USA.

  18. Strong scintillations during atmospheric occultations Theoretical intensity spectra. [radio scattering during spacecraft occultations by planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hinson, D. P.

    1986-01-01

    Each of the two Voyager spacecraft launched in 1977 has completed a reconnaissance of the Jovian and Saturnian systems. In connection with occultation experiments, strong scintillations were observed. Further theoretical work is required before these scintillations can be interpreted. The present study is, therefore, concerned with the derivation of a theory for strong scattering during atmospheric occultation experiments, taking into account as fundamental quantity of interest the spatial spectrum (or spectral density) of intensity fluctuations. Attention is given to a theory for intensity spectra, and numerical calculations. The new formula derived for Phi-i accounts for strong scattering of electromagnetic waves during atmospheric occultations.

  19. [Sensitometry of Mammographic Screen-film System Using Bootstrap Aluminum Step-Wedge.].

    PubMed

    Abe, Shinji; Imada, Ryou; Terauchi, Takashi; Fujisaki, Tatsuya; Monma, Masahiko; Nishimura, Katsuyuki; Saitoh, Hidetoshi; Mochizuki, Yasuo

    2005-01-01

    Recently, a few types of step-wedges for bootstrap sensitometry with a mammographic screen-film system have been proposed. In this study, the bootstrap sensitometry with the mammographic screen-film system was studied for two types of aluminum step-wedges. Characteristic X-ray energy curves were determined using mammographic and general radiographic aluminum step-wedges devised to prevent scattered X-rays generated from one step penetrating into the region of another one, and dependence of the characteristic curves on the wedges was also discussed. No difference was found in the characteristic curves due to the difference in the step-wedges for mammography and general radiography although there was a slight difference in shape at the shoulder portion for the two types of step-wedges. Therefore, it was concluded that aluminum step-wedges for mammography and general radiography could be employed in bootstrap sensitometry with the mammographic screen-film system. PMID:16479054

  20. Mammographic screening: radiological performance as a precursor to image processing

    NASA Astrophysics Data System (ADS)

    Gale, Alastair G.; Wilson, A. R. M.; Roebuck, E. J.

    1993-07-01

    A key issues in the introduction and development of appropriate image processing techniques in mammography is the establishment of the current performance of radiologists in the area. This is necessary because the utility of machine vision approaches is largely validated by comparison with known radiological performance measures (which may well be variable) on the same set of cases. Furthermore the determination of weaknesses in existing human mammographic interpretative ability will demonstrate where machine vision approaches are currently most needed and thus likely to be of maximum benefit in a breast screening program. Following the introduction of breast screening in the U.K. a national self-assessment program has been implemented for all radiologists involved in this specialty. One of the outcomes of this program is the determination of radiological performance variations on this standard task. It is argued that these demonstrate the need for any machine vision approach to take such individuality into account before it can be implemented usefully.

  1. Decision trees and integrated features for computer aided mammographic screening

    SciTech Connect

    Kegelmeyer, W.P. Jr.; Groshong, B.; Allmen, M.; Woods, K.

    1997-02-01

    Breast cancer is a serious problem, which in the United States causes 43,000 deaths a year, eventually striking 1 in 9 women. Early detection is the only effective countermeasure, and mass mammography screening is the only reliable means for early detection. Mass screening has many shortcomings which could be addressed by a computer-aided mammographic screening system. Accordingly, we have applied the pattern recognition methods developed in earlier investigations of speculated lesions in mammograms to the detection of microcalcifications and circumscribed masses, generating new, more rigorous and uniform methods for the detection of both those signs. We have also improved the pattern recognition methods themselves, through the development of a new approach to combinations of multiple classifiers.

  2. A spatial shape constrained clustering method for mammographic mass segmentation.

    PubMed

    Lou, Jian-Yong; Yang, Xu-Lei; Cao, Ai-Ze

    2015-01-01

    A novel clustering method is proposed for mammographic mass segmentation on extracted regions of interest (ROIs) by using deterministic annealing incorporating circular shape function (DACF). The objective function reported in this study uses both intensity and spatial shape information, and the dominant dissimilarity measure is controlled by two weighting parameters. As a result, pixels having similar intensity information but located in different regions can be differentiated. Experimental results shows that, by using DACF, the mass segmentation results in digitized mammograms are improved with optimal mass boundaries, less number of noisy patches, and computational efficiency. An average probability of segmentation error of 7.18% for well-defined masses (or 8.06% for ill-defined masses) was obtained by using DACF on MiniMIAS database, with 5.86% (or 5.55%) and 6.14% (or 5.27%) improvements as compared to the standard DA and fuzzy c-means methods. PMID:25737739

  3. Computerized analysis of mammographic parenchymal patterns using fractal analysis

    NASA Astrophysics Data System (ADS)

    Li, Hui; Giger, Maryellen L.; Huo, Zhimin; Olopade, Olufunmilayo I.; Chinander, Michael R.; Lan, Li; Bonta, Ioana R.

    2003-05-01

    Mammographic parenchymal patterns have been shown to be associated with breast cancer risk. Fractal-based texture analyses, including box-counting methods and Minkowski dimension, were performed within parenchymal regions of normal mammograms of BRCA1/BRCA2 gene mutation carriers and within those of women at low risk for developing breast cancer. Receiver Operating Characteristic (ROC) analysis was used to assess the performance of the computerized radiographic markers in the task of distinguishing between high and low-risk subjects. A multifractal phenomenon was observed with the fractal analyses. The high frequency component of fractal dimension from the conventional box-counting technique yielded an Az value of 0.84 in differentiating between two groups, while using the LDA to estimate the fractal dimension yielded an Az value of 0.91 for the high frequency component. An Az value of 0.82 was obtained with fractal dimensions extracted using the Minkowski algorithm.

  4. Altimetry Using GPS-Reflection/Occultation Interferometry

    NASA Technical Reports Server (NTRS)

    Cardellach, Estel; DeLaTorre, Manuel; Hajj, George A.; Ao, Chi

    2008-01-01

    A Global Positioning System (GPS)- reflection/occultation interferometry was examined as a means of altimetry of water and ice surfaces in polar regions. In GPS-reflection/occultation interferometry, a GPS receiver aboard a satellite in a low orbit around the Earth is used to determine the temporally varying carrier- phase delay between (1) one component of a signal from a GPS transmitter propagating directly through the atmosphere just as the GPS transmitter falls below the horizon and (2) another component of the same signal, propagating along a slightly different path, reflected at glancing incidence upon the water or ice surface.

  5. Investigation of support vector machine for the detection of architectural distortion in mammographic images

    NASA Astrophysics Data System (ADS)

    Guo, Q.; Shao, J.; Ruiz, V.

    2005-01-01

    This paper investigates detection of architectural distortion in mammographic images using support vector machine. Hausdorff dimension is used to characterise the texture feature of mammographic images. Support vector machine, a learning machine based on statistical learning theory, is trained through supervised learning to detect architectural distortion. Compared to the Radial Basis Function neural networks, SVM produced more accurate classification results in distinguishing architectural distortion abnormality from normal breast parenchyma.

  6. Metabolic syndrome and mammographic density in Mexican women

    PubMed Central

    Rice, Megan; Biessy, Carine; Lajous, Martin; Bertrand, Kimberly A.; Tamimi, Rulla M.; Torres-Mejía, Gabriela; López-Ridaura, Ruy; Romieu, Isabelle

    2014-01-01

    Background Metabolic syndrome has been associated with an increased risk of breast cancer; however little is known about the association between metabolic syndrome and percent mammographic density, a strong predictor of breast cancer. Methods We analyzed cross-sectional data from 789 premenopausal and 322 postmenopausal women in the Mexican Teacher's Cohort (ESMaestras). Metabolic syndrome was defined according to the harmonized definition. We measured percent density on mammograms using a computer-assisted thresholding method. Multivariable linear regression was used to estimate the association between density and metabolic syndrome, as well as its components by state (Jalisco, Veracruz) and menopausal status (premenopausal, postmenopausal). Results Among premenopausal women in Jalisco, women with metabolic syndrome had higher percent density compared to those without after adjusting for potential confounders including BMI (difference = 4.76, 95%CI: 1.72, 7.81). Among the metabolic syndrome components, only low high-density lipoprotein levels (<50mg/dl) were associated with significantly higher percent density among premenopausal women in Jalisco (difference=4.62, 95%CI: 1.73, 7.52). Metabolic syndrome was not associated with percent density among premenopausal women in Veracruz (difference=-2.91, 95% CI: -7.19, 1.38), nor among postmenopausal women in either state. Conclusion Metabolic syndrome was associated with higher percent density among premenopausal women in Jalisco, Mexico, but was not associated with percent density among premenopausal women in Veracruz, Mexico or among postmenopausal women in either Jalisco or Veracruz. These findings provide some support for a possible role of metabolic syndrome in mammographic density among premenopausal women; however results were inconsistent across states and require further confirmation in larger studies. PMID:23682074

  7. Prevalence of Mammographically Dense Breasts in the United States

    PubMed Central

    Gangnon, Ronald E.; Burt, Veronica; Trentham-Dietz, Amy; Hampton, John M.; Wellman, Robert D.; Kerlikowske, Karla; Miglioretti, Diana L.

    2014-01-01

    Background National legislation is under consideration that would require women with mammographically dense breasts to be informed of their breast density and encouraged to discuss supplemental breast cancer screening with their health care providers. The number of US women potentially affected by this legislation is unknown. Methods We determined the mammographic breast density distribution by age and body mass index (BMI) using data from 1518 599 mammograms conducted from 2007 through 2010 at mammography facilities in the Breast Cancer Surveillance Consortium (BCSC). We applied these breast density distributions to age- and BMI-specific counts of the US female population derived from the 2010 US Census and the National Health and Nutrition Examination Survey (NHANES) to estimate the number of US women with dense breasts. Results Overall, 43.3% (95% confidence interval [CI] = 43.1% to 43.4%) of women 40 to 74 years of age had heterogeneously or extremely dense breasts, and this proportion was inversely associated with age and BMI. Based on the age and BMI distribution of US women, we estimated that 27.6 million women (95% CI = 27.5 to 27.7 million) aged 40 to 74 years in the United States have heterogeneously or extremely dense breasts. Women aged 40 to 49 years (N = 12.3 million) accounted for 44.3% of this group. Conclusion The prevalence of dense breasts among US women of common breast cancer screening ages exceeds 25 million. Policymakers and healthcare providers should consider this large prevalence when debating breast density notification legislation and designing strategies to ensure that women who are notified have opportunities to evaluate breast cancer risk and discuss and pursue supplemental screening options if deemed appropriate. PMID:25217577

  8. Metabolic syndrome and mammographic density in Mexican women.

    PubMed

    Rice, Megan S; Biessy, Carine; Lajous, Martin; Bertrand, Kimberly A; Tamimi, Rulla M; Torres-Mejía, Gabriela; López-Ridaura, Ruy; Romieu, Isabelle

    2013-07-01

    Metabolic syndrome has been associated with an increased risk of breast cancer; however, little is known about the association between metabolic syndrome and percent mammographic density, a strong predictor of breast cancer. We analyzed cross-sectional data from 789 premenopausal and 322 postmenopausal women in the Mexican Teacher's Cohort (ESMaestras). Metabolic syndrome was defined according to the harmonized definition. We measured percent density on mammograms using a computer-assisted thresholding method. Multivariable linear regression was used to estimate the association between density and metabolic syndrome, as well as its components by state (Jalisco, Veracruz) and menopausal status (premenopausal, postmenopausal). Among premenopausal women in Jalisco, women with metabolic syndrome had higher percent density than those without after adjusting for potential confounders including BMI [difference = 4.76; 95% confidence interval (CI), 1.72-7.81]. Among the metabolic syndrome components, only low high-density lipoprotein levels (<50 mg/dL) were associated with significantly higher percent density among premenopausal women in Jalisco (difference = 4.62; 95% CI, 1.73-7.52). Metabolic syndrome was not associated with percent density among premenopausal women in Veracruz (difference = -2.91; 95% CI, -7.19 to 1.38), nor among postmenopausal women in either state. Metabolic syndrome was associated with higher percent density among premenopausal women in Jalisco, Mexico, but was not associated with percent density among premenopausal women in Veracruz, Mexico, or among postmenopausal women in either Jalisco or Veracruz. These findings provide some support for a possible role of metabolic syndrome in mammographic density among premenopausal women; however, results were inconsistent across states and require further confirmation in larger studies.

  9. Mammographic Density and Prediction of Nodal Status in Breast Cancer Patients.

    PubMed

    Hack, C C; Häberle, L; Geisler, K; Schulz-Wendtland, R; Hartmann, A; Fasching, P A; Uder, M; Wachter, D L; Jud, S M; Loehberg, C R; Lux, M P; Rauh, C; Beckmann, M W; Heusinger, K

    2013-02-01

    Aim: Nodal status remains one of the most important prognostic factors in breast cancer. The cellular and molecular reasons for the spread of tumor cells to the lymph nodes are not well understood and there are only few predictors in addition to tumor size and multifocality that give an insight into additional mechanisms of lymphatic spread. Aim of our study was therefore to investigate whether breast characteristics such as mammographic density (MD) add to the predictive value of the presence of lymph node metastases in patients with primary breast cancer. Methods: In this retrospective study we analyzed primary, metastasis-free breast cancer patients from one breast center for whom data on MD and staging information were available. A total of 1831 patients were included into this study. MD was assessed as percentage MD (PMD) using a semiautomated method and two readers for every patient. Multiple logistic regression analyses with nodal status as outcome were used to investigate the predictive value of PMD in addition to age, tumor size, Ki-67, estrogen receptor (ER), progesterone receptor (PR), grading, histology, and multi-focality. Results: Multifocality, tumor size, Ki-67 and grading were relevant predictors for nodal status. Adding PMD to a prediction model which included these factors did not significantly improve the prediction of nodal status (p = 0.24, likelihood ratio test). Conclusion: Nodal status could be predicted quite well with the factors multifocality, tumor size, Ki-67 and grading. PMD does not seem to play a role in the lymphatic spread of tumor cells. It could be concluded that the amount of extracellular matrix and stromal cell content of the breast which is reflected by MD does not influence the probability of malignant breast cells spreading from the primary tumor to the lymph nodes.

  10. Hematologic malignancies

    SciTech Connect

    Hoogstraten, B.

    1986-01-01

    The principle aim of this book is to give practical guidelines to the modern treatment of the six important hematologic malignancies. Topics considered include the treatment of the chronic leukemias; acute leukemia in adults; the myeloproliferative disorders: polycythemia vera, essential thrombocythemia, and idiopathic myelofibrosis/agnogenic myeloid metaplasia; Hodgkin's Disease; non-Hodgkin's lymphoma; and Multiple Myeloma.

  11. Malignant hyperthermia.

    PubMed

    Taiclet, L

    1985-01-01

    Despite numerous reviews and clinical reports, much remains to be learned about the cause, treatment, and prevention of malignant hyperthermia.Among the most worrisome concerns of the clinician administering anesthesia is the malignant hyperthermia crisis. When it arises, it is always frightening-and sometimes fatal. Usually occurring very suddenly and without warning, malignant hyperthermia is considered to be a hypercatabolic crisis; the condition is known to affect humans and certain breeds of pigs. The exact triggering mechanisms of malignant hyperthermia (MH) in humans are not known, but a crisis can be initiated by volatile general anesthetics, neuromuscular blocking agents, and amide local anesthetics. Although a history of an MH crisis is a diagnostic aid, previous uneventful exposure to anesthesia does not guarantee the safety of the patient in subsequent anesthetic procedures.(1) For these reasons, it is important for the anesthesiologist to be aware of the initial signs of MH and to be prepared to provide immediate treatment to reverse such a crisis. PMID:3865561

  12. Malignant hyperthermia.

    PubMed Central

    Ben Abraham, R.; Adnet, P.; Glauber, V.; Perel, A.

    1998-01-01

    Malignant hyperthermia is a rare autosomal dominant trait that predisposes affected individuals to great danger when exposed to certain anaesthetic triggering agents (such as potent volatile anaesthetics and succinylcholine). A sudden hypermetabolic reaction in skeletal muscle leading to hyperthermia and massive rhabdomyolysis can occur. The ultimate treatment is dantrolene sodium a nonspecific muscle relaxant. Certain precautions should be taken before anaesthesia of patients known to be susceptible to malignant hyperthermia. These include the prohibition of the use of triggering agents, monitoring of central body temperature and expired CO2, and immediate availability of dantrolene. In addition, careful cleansing of the anaesthesia machine of vapours of halogenated agents is recommended. If these measures are taken, the chances of an MH episode are greatly reduced. When malignant hyperthermia-does occur in the operating room, prompt recognition and treatment usually prevent a potentially fatal outcome. The most reliable test to establish susceptibility to malignant hyperthermia is currently the in vitro caffeine-halothane contracture test. It is hoped that in the future a genetic test will be available. PMID:9538480

  13. An Investigation into the Consistency in Mammographic Density Identification by Radiologists: Effect of Radiologist Expertise and Mammographic Appearance.

    PubMed

    Li, Yanpeng; Brennan, Patrick C; Lee, Warwick; Nickson, Carolyn; Pietrzyk, Mariusz W; Ryan, Elaine A

    2015-10-01

    The aim of this work is to investigate how radiologist expertise and image appearance may have an impact on inter-reader variability of mammographic density (MD) identification. Seventeen radiologists, divided into three expertise groups, were asked to manually segment the areas they consider to be MD in 40 clinical images. The variation in identification of MD for each image was quantified by finding the range of segmentation areas. The impact of radiologist expertise and image appearance on this variation was explored. The range of areas chosen by participating radiologists varied from 7 to 73% across the 40 images, with a mean range of 35 ± 13%. Participants with high expertise were more likely to choose similar areas to one another, compared to participants with medium and low expertise levels (mean range were 19 ± 10%, 29 ± 13% and 25 ± 14 %, respectively, p < 0.0001). There was a significantly higher average grey level for the area segmented by all radiologists as MD compared to the area of variation, with mean grey level value for 8-bit images being 146 ± 19 vs. 99 ± 14, respectively. MD segmentation borders were consistent in areas where there was a sharp intensity change within a short distance. In conclusion, radiologists with high expertise tend to have a higher agreement when identifying MD. Tissues which have a lower contrast and a less visually sharp gradient change at the interface between high density tissue and adipose background lead to inter-reader variation in choosing mammographic density.

  14. Occult spondyloarthritis in inflammatory bowel disease.

    PubMed

    Bandinelli, Francesca; Manetti, Mirko; Ibba-Manneschi, Lidia

    2016-02-01

    Spondyloarthritis (SpA) is a frequent extra-intestinal manifestation in patients with inflammatory bowel disease (IBD), although its real diffusion is commonly considered underestimated. Abnormalities in the microbioma and genetic predisposition have been implicated in the link between bowel and joint inflammation. Otherwise, up to date, pathogenetic mechanisms are still largely unknown and the exact influence of the bowel activity on rheumatic manifestations is not clearly explained. Due to evidence-based results of clinical studies, the interest on clinically asymptomatic SpA in IBD patients increased in the last few years. Actually, occult enthesitis and sacroiliitis are discovered in high percentages of IBD patients by different imaging techniques, mainly enthesis ultrasound (US) and sacroiliac joint X-ray examinations. Several diagnostic approaches and biomarkers have been proposed in an attempt to correctly classify and diagnose clinically occult joint manifestations and to define clusters of risk for patient screening, although definitive results are still lacking. The correct recognition of occult SpA in IBD requires an integrated multidisciplinary approach in order to identify common diagnostic and therapeutic strategies. The use of inexpensive and rapid imaging techniques, such as US and X-ray, should be routinely included in daily clinical practice and trials to correctly evaluate occult SpA, thus preventing future disability and worsening of quality of life in IBD patients.

  15. Occult gunshot injury of the temporal bone.

    PubMed Central

    Geary, U M; Ritchie, D A; Luke, L C

    1997-01-01

    Increasing firearms violence has produced much public disquiet in recent months and Liverpool has seen a particularly well publicized spate of shootings. This is a case report of an initially occult intracranial injury which illustrates the unpredictable nature of missile trauma and the importance of computerised tomography in all cases of gunshot injury to the head. Images Figure 1 Figure 2 PMID:9193993

  16. Preliminary Results From the Champ Occultation Measurements

    NASA Astrophysics Data System (ADS)

    Hajj, G.; Dong, D.; Iijima, B.; Kuang, D.; Kursinski, R.; Mannucci, A.; Meehan, T.; Romans, L.; de la Torre Juárez, M.; Yunck, T.

    2001-05-01

    Champ collects 200-250 globally distributed GPS occultations every day providing a wealth of information on atmospheric parameters such as pressure, temperature, humidity between 0-60 km altitude and electron density above 60 km altitude. There are several aspects to the Champ occultation measurements which distinguish them from prior measurements (such as from GPS/MET, Oersted and SAC-C): (1) They are taken during solar maximum; (2) they are collected with a new generation receiver ("BlackJack") which provides high quality L1 and L2 measurements even when the DoD anti-spoofing of the GPS signal is turned on; (3) the tracking loop in the receiver is optimized to allow the occulted signal to descend very low in the atmosphere (<1km from the surface). A further distinction comes from the fact that selective availability (the dithering of the GPS clocks) was permanently turned off by DoD, therefore reducing or eliminating the need for 1-second ground measurements previously used to difference out high frequency GPS clock drifts. This talk will present results obtained at JPL from the early Champ occultation data sets, first collected in February, 2001, and will address the specific issues listed above. Specifically, we will present (a) statistics on how low in the atmosphere occultations are able to probe as a function of geographical latitudes and humidity conditions; (b) the limitations on higher altitude atmospheric retrievals (between 30-60 km) caused by the ionosphere at different local times and solar conditions, including comparisons to GPS/MET data taken during solar minimum; (c) individual and statistical comparisons of temperature and water vapor to atmospheric analyses such as NCEP and ECMWF and other data sets such as radiosondes; (d) the impact of including or excluding high rate ground data.

  17. The relative effect of mammographic screening on breast cancer mortality by socioeconomic status

    PubMed Central

    Ripping, Theodora M.; van der Waal, Danielle; Verbeek, André L.M.; Broeders, Mireille J.M.

    2016-01-01

    Abstract Breast cancer incidence and mortality are higher in women with a high socioeconomic status (SES). The potential to prevent death from breast cancer is therefore greater in the high SES group. This does, however, require that the effectiveness of screening in the high SES group is equal to or greater than the effectiveness in the low SES group. The aim of this study is to assess the relative effectiveness of mammographic screening on breast cancer mortality by SES. In Nijmegen, the Netherlands, women are invited to participate in biennial mammographic screening since 1975. Postal code is collected at each round and is used to calculate the SES of each woman based on the SES indicator of the Netherlands Institute for Social Research. The Dutch average was used to classify the SES score of each woman as either high or low. We designed a case-control study to investigate the effect of mammographic screening in women aged 50 to 75, 40 to 75, and 50 to 69 years, and calculated the odds ratios (ORs) and 95% confidence intervals (CIs). Among the women invited to the mammographic screening program in Nijmegen, 10% had a high SES. In women aged 50 to 75 years, the breast cancer death rate was 38% lower in screened women than in unscreened women. The ORs for women with high SES (OR 0.82, 95% CI 0.31–2.19) and low SES did not differ significantly (OR 0.61, 95% CI 0.47–0.78). Mammographic screening reduces breast cancer mortality, but we did not observe a significant difference in the relative effectiveness of screening by SES. If the effectiveness of mammographic screening is indeed not dependent on SES status, the absolute number of breast cancer deaths prevented by mammographic screening will be greater in the high SES than low SES group, because women with a high SES have a greater risk of breast cancer death. PMID:27495038

  18. Novel multiresolution mammographic density segmentation using pseudo 3D features and adaptive cluster merging

    NASA Astrophysics Data System (ADS)

    He, Wenda; Juette, Arne; Denton, Erica R. E.; Zwiggelaar, Reyer

    2015-03-01

    Breast cancer is the most frequently diagnosed cancer in women. Early detection, precise identification of women at risk, and application of appropriate disease prevention measures are by far the most effective ways to overcome the disease. Successful mammographic density segmentation is a key aspect in deriving correct tissue composition, ensuring an accurate mammographic risk assessment. However, mammographic densities have not yet been fully incorporated with non-image based risk prediction models, (e.g. the Gail and the Tyrer-Cuzick model), because of unreliable segmentation consistency and accuracy. This paper presents a novel multiresolution mammographic density segmentation, a concept of stack representation is proposed, and 3D texture features were extracted by adapting techniques based on classic 2D first-order statistics. An unsupervised clustering technique was employed to achieve mammographic segmentation, in which two improvements were made; 1) consistent segmentation by incorporating an optimal centroids initialisation step, and 2) significantly reduced the number of missegmentation by using an adaptive cluster merging technique. A set of full field digital mammograms was used in the evaluation. Visual assessment indicated substantial improvement on segmented anatomical structures and tissue specific areas, especially in low mammographic density categories. The developed method demonstrated an ability to improve the quality of mammographic segmentation via clustering, and results indicated an improvement of 26% in segmented image with good quality when compared with the standard clustering approach. This in turn can be found useful in early breast cancer detection, risk-stratified screening, and aiding radiologists in the process of decision making prior to surgery and/or treatment.

  19. Stellar Occultation Probe of Triton's Atmosphere

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    1998-01-01

    The goals of this research were (i) to better characterize Triton's atmospheric structure by probing a region not well investigated by Voyager and (ii) to begin acquiring baseline data for an investigation of the time evolution of the atmosphere which will set limits on the thermal conductivity of the surface and the total mass of N2 in the atmosphere. Our approach was to use observations (with the Kuiper Airborne Observatory) of a stellar occultation by Triton that was predicted to occur on 1993 July 10. As described in the attached reprint, we achieved these objectives through observation of this occultation and a subsequent one with the KAO in 1995. We found new results about Triton's atmospheric structure from the analysis of the two occultations observed with the KAO and ground-based data. These stellar occultation observations made both in the visible and infrared, have good spatial coverage of Triton including the first Triton central-flash observations, and are the first data to probe the 20-100 km altitude level on Triton. The small-planet light curve model of Elliot and Young (AJ 103, 991-1015) was generalized to include stellar flux refracted by the far limb, and then fitted to the data. Values of the pressure, derived from separate immersion and emersion chords, show no significant trends with latitude indicating that Triton's atmosphere is spherically symmetric at approximately 50 km altitude to within the error of the measurements. However, asymmetry observed in the central flash indicates the atmosphere is not homogeneous at the lowest levels probed (approximately 20 km altitude). From the average of the 1995 occultation data, the equivalent-isothermal temperature of the atmosphere is 47 +/- 1 K and the atmospheric pressure at 1400 km radius (approximately 50 km altitude) is 1.4 +/- 0.1 microbar. Both of these are not consistent with a model based on Voyager UVS and RSS observations in 1989 (Strobel et al, Icarus 120, 266-289). The atmospheric

  20. Association between mammographic density and basal-like and luminal A breast cancer subtypes

    PubMed Central

    2013-01-01

    Introduction Mammographic density is a strong risk factor for breast cancer overall, but few studies have examined the association between mammographic density and specific subtypes of breast cancer, especially aggressive basal-like breast cancers. Because basal-like breast cancers are less frequently screen-detected, it is important to understand how mammographic density relates to risk of basal-like breast cancer. Methods We estimated associations between mammographic density and breast cancer risk according to breast cancer subtype. Cases and controls were participants in the Carolina Breast Cancer Study (CBCS) who also had mammograms recorded in the Carolina Mammography Registry (CMR). A total of 491 cases had mammograms within five years prior to and one year after diagnosis and 528 controls had screening or diagnostic mammograms close to the dates of selection into CBCS. Mammographic density was reported to the CMR using Breast Imaging Reporting and Data System categories. The expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 1 and 2 (HER1 and HER2), and cytokeratin 5/6 (CK5/6) were assessed by immunohistochemistry and dichotomized as positive or negative, with ER+ and/or PR+, and HER2- tumors classified as luminal A and ER-, PR-, HER2-, HER1+ and/or CK5/6+ tumors classified as basal-like breast cancer. Triple negative tumors were defined as negative for ER, PR and HER2. Of the 491 cases 175 were missing information on subtypes; the remaining cases included 181 luminal A, 17 luminal B, 48 basal-like, 29 ER-/PR-/HER2+, and 41 unclassified subtypes. Odds ratios comparing each subtype to all controls and case-case odds ratios comparing mammographic density distributions in basal-like to luminal A breast cancers were estimated using logistic regression. Results Mammographic density was associated with increased risk of both luminal A and basal-like breast cancers, although estimates were imprecise. The

  1. Malignant hyperthermia.

    PubMed

    Cantin, R Y; Poole, A; Ryan, J F

    1986-10-01

    The increasing use of intravenous and inhalation sedation in the dental office has the potential of increasing the incidence of malignant hyperthermia (MH) in susceptible subjects. The object of this article is to present two cases of MH and to discuss its pathophysiology, its clinical picture, and its management in the light of the current literature. Stringent screening procedures should be adopted and maintained in order to channel suspected cases to appropriate centers for expert consultation and management. It is further advocated that a program of education for patients and their families be instituted, as it is an essential prerequisite of effective prophylaxis. PMID:2946013

  2. Local mammographic density as a predictor of breast cancer

    NASA Astrophysics Data System (ADS)

    Otsuka, Mayu; Harkness, Elaine F.; Chen, Xin; Moschidis, Emmanouil; Bydder, Megan; Gadde, Soujanya; Lim, Yit Y.; Maxwell, Anthony J.; Evans, Gareth D.; Howell, Anthony; Stavrinos, Paula; Wilson, Mary; Astley, Susan M.

    2015-03-01

    High overall mammographic density is associated with both an increased risk of developing breast cancer and the risk of cancer being masked. We compared local density at cancer sites in diagnostic images with corresponding previous screening mammograms (priors), and matched controls. VolparaTM density maps were obtained for 54 mammograms showing unilateral breast cancer and their priors which had been previously read as normal. These were each matched to 3 controls on age, menopausal status, hormone replacement therapy usage, body mass index and year of prior. Local percent density was computed in 15mm square regions at lesion sites and similar locations in the corresponding images. Conditional logistic regression was used to predict case-control status. In diagnostic and prior images, local density was increased at the lesion site compared with the opposite breast (medians 21.58%, 9.18%, p<0.001 diagnostic; 18.82%, 9.45%, p <0.001 prior). Women in the highest tertile of local density in priors were more likely to develop cancer than those in the lowest tertile (OR 42.09, 95% CI 5.37-329.94). Those in the highest tertile of VolparaTM gland volume were also more likely to develop cancer (OR 2.89, 95% CI 1.30-6.42). Local density is increased where cancer will develop compared with corresponding regions in the opposite breast and matched controls, and its measurement could enhance computer-aided mammography.

  3. Mammographic Breast Density Patterns in Asymptomatic Mexican Women

    PubMed Central

    Calderón-Garcidueñas, Ana Laura; Sanabria-Mondragón, Mónica; Hernández-Beltrán, Lourdes; López-Amador, Noé; Cerda-Flores, Ricardo M.

    2012-01-01

    Breast density (BD) is a risk factor for breast cancer. Aims. To describe BD patterns in asymptomatic Mexican women and the pathological mammographic findings. Methods and Material. Prospective, descriptive, and comparative study. Women answered a questionnaire and their mammograms were analyzed according to BI-RADS. Univariate (χ2) and conditional logistic regression analyses were performed. Results. In 300 women studied the BD patterns were fat 56.7% (170), fibroglandular 29% (87), heterogeneously dense 5.7% (17), and dense pattern 8.6% (26). Prevalence of fat pattern was significantly different in women under 50 years (37.6%, 44/117) and older than 50 (68.8%, 126/183). Patterns of high breast density (BD) (dense + heterogeneously dense) were observed in 25.6% (30/117) of women ≤50 years and 7.1% (13/183) of women >50. Asymmetry in BD was observed in 22% (66/300). Compression cone ruled out underlying disease in 56 cases. In the remaining 10, biopsy revealed one fibroadenoma, one complex cyst, and 6 invasive and 2 intraductal carcinomas. 2.6% (8/300) of patients had non-palpable carcinomas. Benign lesions were observed in 63.3% (190/300) of cases, vascular calcification in 150 cases (78.9%), and fat necrosis in 38 cases (20%). Conclusions. Mexican women have a low percentage of high-density patterns. PMID:23346398

  4. Monochromatic Mammographic Imaging Using X-Ray Polycapillary Optics

    NASA Astrophysics Data System (ADS)

    Sugiro, Francisca

    2002-06-01

    Monochromatic imaging is typically done with synchrotron sources. These sources are expensive and not practical for clinical settings. However, conventional laboratory sources normally have insufficient intensity. Polycapillary x-ray optics can be used to efficiently produce an intense parallel beam, which can be diffracted from a crystal to create monochromatic radiation. Monochromatic parallel beam imaging produces high subject contrast, high resolution, and low patient dose. Contrast, resolution, and intensity measurements were performed with both high and low angular acceptance crystals. Testing was first done at 8 keV with an intense copper rotating anode source. Preliminary l7.5 kev measurements were then made with a molybdenum source. At 8 keV, contrast enhancement was a factor of five relative to the polychromatic case, in good agreement with theoretical values. At l7.5 kev, monochromatic subject contrast was a factor of two times greater than the conventional polychromatic contrast. The measured angular resolution with a silicon crystal is 0.6 mrad at 8 keV, and 0.2 - 0.3 mrad at 17.5 keV. For a 50-mm thick patient, this angle corresponds to 50 lp/mm with an ideal detector. The use of polychromatic collimating optics allow monochromatic mammographic imaging measurements with a conventional x-ray source in a practical clinical setting.

  5. Mammographic density and risk of breast cancer in Korean women.

    PubMed

    Kim, Bo-Kyoung; Choi, Yoon-Ho; Nguyen, Tuong L; Nam, Seok Jin; Lee, Jeong Eon; Hopper, John L; Sung, Joohon; Song, Yun-Mi

    2015-09-01

    We carried out this study to evaluate the association between mammographic density adjusted for age and BMI and early-onset breast cancer in Asian women. We recruited 213 Korean patients with breast cancer (45% diagnosed before the age of 50 years) and 630 controls matched for age, menopausal status, and examination date. The percentage and absolute size of dense areas on digital mammograms were measured using a computer-assisted thresholding technique (Cumulus). We carried out an analysis using the conditional logistic regression model with adjustment for covariates. An increase by 1 SD in age and BMI-adjusted absolute dense area and percentage dense area was associated with a 1.15-fold (95% confidence interval: 1.03, 1.29) and 1.20-fold (95% confidence interval: 1.06, 1.37) increased risk of breast cancer, respectively. These associations were stronger for premenopausal disease (P=0.07 and 0.01, respectively) and for disease diagnosed before age 50 (P=0.07 and 0.02, respectively) than for postmenopausal disease (P=0.16 and 0.23, respectively) or later onset disease (P=0.10 and 0.10, respectively). There was no difference in the associations with premenopausal versus postmenopausal and early-onset versus late-onset disease. After adjusting for age and BMI, both a greater absolute dense area and a greater percentage dense area were associated with an increased risk of breast cancer, particularly at a young age.

  6. Predicting breast cancer risk using mammographic density measurements from both mammogram sides and views.

    PubMed

    Stone, Jennifer; Ding, Jane; Warren, Ruth M L; Duffy, Stephen W

    2010-11-01

    Mammographic density is a strong risk factor for breast cancer. Which and how many x-rays are used for research, and how mammographic density is measured varies across studies. In this article, we compared three different measurements (absolute dense area, percent dense area and percent dense volume) from each of four mammograms [left, right, medio-lateral oblique (MLO) and cranio-caudal (CC) views] using three different methods of measurement [computer-assisted thresholding, visual assessment and standard mammogram form (SMF)] to investigate whether additional measurements and/or different methods of measurement provide more information in the prediction of breast cancer risk. Mammographic density was measured in all four mammograms from 318 cases and 899 age-matched controls combined from the Cambridge and Norwich Breast Screening Programmes. Measurements were averaged across various combinations of mammogram type and/or view. Conditional logistic regression was used to estimate odds ratios associated with increasing quintiles of each mammographic measure. Overall, there appeared to be no difference in the fit of the models using two or four mammograms compared to the models using just the contralateral MLO or CC mammogram (all P > 0.07) for all methods of measurement. Common practice of measuring just the contralateral MLO or CC mammogram for analysis in case-control studies investigating the association between mammographic density and breast cancer risk appears to be sufficient.

  7. Associations of mammographic dense and nondense areas and body mass index with risk of breast cancer.

    PubMed

    Baglietto, Laura; Krishnan, Kavitha; Stone, Jennifer; Apicella, Carmel; Southey, Melissa C; English, Dallas R; Hopper, John L; Giles, Graham G

    2014-02-15

    Mammographic density measurements are associated with risk of breast cancer. Few studies have investigated the concurrent associations of mammographic dense and nondense areas, body mass index (weight (kg)/height (m)(2)), and ages at mammogram and diagnosis with breast cancer risk. We conducted a matched, case-control study nested within the Melbourne Collaborative Cohort Study (cohort recruitment in 1990-1994 and follow-up until 2007) to estimate the associations between these factors and breast cancer risk under alternative causal models. Mammographic dense area was positively associated with risk, and the strength of this association was only slightly influenced by the choice of the causal model (relative risk per 1 standard deviation = 1.50, 95% confidence interval: 1.32, 1.70). Mammographic nondense area was inversely associated with risk under the assumption that fat in the body and fat in the breast cause breast cancer through independent mechanisms (relative risk per 1 standard deviation = 0.75, 95% confidence interval: 0.65, 0.86), whereas it was not associated with risk under the assumption that they are both proxies of adiposity. Knowledge about the biological mechanisms regulating the role played by mammographic nondense area and body fat on breast cancer risk is essential to better estimate their impacts on individual risk.

  8. Unsuccesfull occultation observation of stars by asteroids

    NASA Astrophysics Data System (ADS)

    Gaina, Alex; Maley, Paul D.

    2010-12-01

    A report is given about an attempt to observe occultations of stars HIP 7268 and TYC1868-02234-01 by asteroids Tisiphone and Thisbe on 3 november 2010 in Chisinau, The Republic of Moldova, which was placed very close to the central line of the occultations in spite of. The main cause of the insucces was weather. Few days before a cyclon developed above the Black Sea, while above the Western Europe, including Greece the sky was covered during many days. Some critics are made concerning the preparation of astronomical facilities in the Republic of Moldova for succesfull observations. The meteo conditions in Lozova-Ciuciuleni were better, but bad, than in other parts of the Republic of Moldova.

  9. Occult fractures of the knee: tomographic evaluation

    SciTech Connect

    Apple, J.S.; Martinez, S.; Allen, N.B.; Caldwell, D.S.; Rice, J.R.

    1983-08-01

    Seven adults with painful effusions of the knee were examined for occult fractures using pluridirectional tomograph in the coronal and lateral planes. Six patients (ages 50 to 82 years) were osteopenic and gave histories ranging from none to mild trauma; one 26-year-old man was not osteopenic and had severe trauma. In all cases, routine radiographs were interpreted as negative, but tomography demonstrated a fracture. Five fractures were subchondral. Bone scans in 2 patients were positive. The authors conclude that osteopenic patients with a painful effusion of the knee should be considered to have an occult fracture. While bone scans may be helpful, tomography is recommended as the procedure of choice to define the location and extent of the fracture.

  10. Malignant hyperthermia

    PubMed Central

    2012-01-01

    Malignant hyperthermia (MH) is an uncommon, life-threatening pharmacogenetic disorder of the skeletal muscle. It presents as a hypermetabolic response in susceptible individuals to potent volatile anesthetics with/without depolarizing muscle relaxants; in rare cases, to stress from exertion or heat stress. Susceptibility to malignant hyperthermia (MHS) is inherited as an autosomally dominant trait with variable expression and incomplete penetrance. It is known that the pathophysiology of MH is related to an uncontrolled rise of myoplasmic calcium, which activates biochemical processes resulting in hypermetabolism of the skeletal muscle. In most cases, defects in the ryanodine receptor are responsible for the functional changes of calcium regulation in MH, and more than 300 mutations have been identified in the RYR1 gene, located on chromosome 19q13.1. The classic signs of MH include increase of end-tidal carbon dioxide, tachycardia, skeletal muscle rigidity, tachycardia, hyperthermia and acidosis. Up to now, muscle contracture test is regarded as the gold standard for the diagnosis of MHS though molecular genetic test is used, on a limited basis so far to diagnose MHS. The mortality of MH is dramatically decreased from 70-80% to less than 5%, due to an introduction of dantrolene sodium for treatment of MH, early detection of MH episode using capnography, and the introduction of diagnostic testing for MHS. This review summarizes the clinically essential and important knowledge of MH, and presents new developments in the field. PMID:23198031

  11. CASSINI UVIS STELLAR OCCULTATION OBSERVATIONS OF SATURN's RINGS

    SciTech Connect

    Colwell, J. E.; Jerousek, R. G.; Pettis, D.; Bradley, E. T.; Esposito, L. W.; Sremcevic, M.

    2010-12-15

    The Cassini spacecraft's Ultraviolet Imaging Spectrograph (UVIS) includes a high-speed photometer (HSP) that has observed more than 100 stellar occultations by Saturn's rings. Here, we document a standardized technique applied to the UVIS-HSP ring occultation datasets delivered to the Planetary Data System as higher level data products. These observations provide measurements of ring structure that approaches the scale of the largest common ring particles ({approx}5 m). The combination of multiple occultations at different viewing geometries enables reconstruction of the three-dimensional structure of the rings. This inversion of the occultation data depends on accurate calibration of the data so that occultations of different stars taken at different times and under different viewing conditions can be combined to retrieve ring structure. We provide examples of the structure of the rings as seen from several occultations at different incidence angles to the rings, illustrating changes in the apparent structure with viewing geometry.

  12. Potential KBO Stellar Occultations: 2011-2015

    NASA Astrophysics Data System (ADS)

    Zangari, Amanda; Zuluaga, C. A.; Gulbis, A. A. S.; Elliot, J. L.; Person, M. J.; Bosh, A. S.

    2010-10-01

    We present the results of an occultation candidate search of the UCAC2 catalog for over 30 Kuiper Belt Objects and Centaurs [not including (134340) Pluto]. KBOs were selected based on absolute magnitude, distance from the sun and the number of oppositions observed. This search identified occultation candidate stars within 2.5 arcseconds of each minor planet's path from 2011-2015. As typical UCAC2 catalog uncertainties ranged from 0.05 to 0.5 arcseconds, and KBO ephemeris uncertainties for a well-observed object ranged from 0.2 to 0.6 arcseconds, this study seeks to identify the most promising potential occultations for further astrometric follow-up. Additional observations of stars and the potentially occulting body help determine the necessary star offsets and ephemeris corrections. Events have been grouped into the following categories: near-geocentric (any brightness), near-misses, stars of magnitude 13 or brighter (the dimmest star feasible with a large portable telescope), slow events, and events observable from telescope-rich regions of the Earth. These categories allow for planning campaigns involving wide-spread portable and fixed telescopes, or an airborne telescope (such as SOFIA). The two most promising events are an encounter of (28978) Ixion with a 10.63 magnitude star on 2012-04-16 and (84922) 2003 VS2 with a 14.83 magnitude star on 2011-11-01. KBOs such as (50000) Quaoar, (28978) Ixion, (55638) 2002 VE95, and (84922) 2003 VS2 encounter over 50 UCAC2 stars in the next five years and should be most carefully monitored. This work was supported, in part by NASA Grant NNX10AB27G.

  13. Study of transneptunian objects through stellar occultations

    NASA Astrophysics Data System (ADS)

    Benedetti-Rossi, G.; Sicardy, B.; Braga-Ribas, F.

    2014-07-01

    The physical parameters of the transneptunian objects (TNO's) such as size, shape, density, presence of atmosphere, provide important information on their formation and evolution. At more than 30 astronomical units (au) from the Sun, those objects receive low solar radiation and have low mutual collisions so they can be considered as remnants of the primordial outer Solar System. Besides that, information on TNO's is of great relevance when trying to establish a general formation scenario for the recently discovered planetary systems. The problem is that such bodies have a diameter smaller than 2300 km (Eris, one of the largest TNO, has 2326 km) and, when viewed from Earth, they subtend angles smaller than 50 milli-arcseconds, a fact that makes their resolution very poor with current imaging systems. One method to obtain very accurate information on the TNO's is the stellar-occultation technique. Sizes at kilometer accuracies and pressure at nanobar levels can be achieved with this method. Shape, mass, density and other physical parameters can also be derived using this technique. Since 2010, we observed stellar occultations of several TNO's (Varuna in 2010 and 2013; Eris in 2010; 2003 AZ_{84} in 2010 and 2011; Makemake in 2011; Quaoar in 2011 and two in 2012; 2002 KX_{14} in 2013; and finally Sedna in 2013) besides some other occultations of the Pluto system and of the largest Centaurs. We also predicted future events in 2014 and 2015 for the largest 40 TNO's and Centaurs. In this work, we will present new results obtained from recent stellar occultations of TNO's.

  14. The JWST/NIRCam coronagraph flight occulters

    NASA Astrophysics Data System (ADS)

    Krist, John E.; Balasubramanian, Kunjithapatham; Muller, Richard E.; Shaklan, Stuart B.; Kelly, Douglas M.; Wilson, Daniel W.; Beichman, Charles A.; Serabyn, Eugene; Mao, Yalan; Echternach, Pierre M.; Trauger, John T.; Liewer, Kurt M.

    2010-07-01

    The NIRCam instrument on the James Webb Space Telescope will have a Lyot coronagraph for high contrast imaging of extrasolar planets and circumstellar disks at λ=2 - 5 μm. Half-tone patterns are used to create graded-transmission image plane masks. These are generated using electron beam lithography and reactive ion etching of a metal layer on an antireflection coated sapphire substrate. We report here on the manufacture and evaluation of the flight occulters.

  15. Predicting error in detecting mammographic masses among radiology trainees using statistical models based on BI-RADS features

    SciTech Connect

    Grimm, Lars J. Ghate, Sujata V.; Yoon, Sora C.; Kim, Connie; Kuzmiak, Cherie M.; Mazurowski, Maciej A.

    2014-03-15

    Purpose: The purpose of this study is to explore Breast Imaging-Reporting and Data System (BI-RADS) features as predictors of individual errors made by trainees when detecting masses in mammograms. Methods: Ten radiology trainees and three expert breast imagers reviewed 100 mammograms comprised of bilateral medial lateral oblique and craniocaudal views on a research workstation. The cases consisted of normal and biopsy proven benign and malignant masses. For cases with actionable abnormalities, the experts recorded breast (density and axillary lymph nodes) and mass (shape, margin, and density) features according to the BI-RADS lexicon, as well as the abnormality location (depth and clock face). For each trainee, a user-specific multivariate model was constructed to predict the trainee's likelihood of error based on BI-RADS features. The performance of the models was assessed using area under the receive operating characteristic curves (AUC). Results: Despite the variability in errors between different trainees, the individual models were able to predict the likelihood of error for the trainees with a mean AUC of 0.611 (range: 0.502–0.739, 95% Confidence Interval: 0.543–0.680,p < 0.002). Conclusions: Patterns in detection errors for mammographic masses made by radiology trainees can be modeled using BI-RADS features. These findings may have potential implications for the development of future educational materials that are personalized to individual trainees.

  16. Region based stellate features combined with variable selection using AdaBoost learning in mammographic computer-aided detection.

    PubMed

    Kim, Dae Hoe; Choi, Jae Young; Ro, Yong Man

    2015-08-01

    In this paper, a new method is developed for extracting so-called region-based stellate features to correctly differentiate spiculated malignant masses from normal tissues on mammograms. In the proposed method, a given region of interest (ROI) for feature extraction is divided into three individual subregions, namely core, inner, and outer parts. The proposed region-based stellate features are then extracted to encode the different and complementary stellate pattern information by computing the statistical characteristics for each of the three different subregions. To further maximize classification performance, a novel variable selection algorithm based on AdaBoost learning is incorporated for choosing an optimal subset of variables of region-based stellate features. In particular, we develop a new variable selection metric (criteria) that effectively determines variable importance (ranking) within the conventional AdaBoost framework. Extensive and comparative experiments have been performed on the popular benchmark mammogram database (DB). Results show that our region-based stellate features (extracted from automatically segmented ROIs) considerably outperform other state-of-the-art features developed for mammographic spiculated mass detection or classification. Our results also indicate that combining region-based stellate features with the proposed variable selection strategy has an impressive effect on improving spiculated mass classification and detection.

  17. Changes in Pluto's Atmosphere Revealed by Occultations

    NASA Astrophysics Data System (ADS)

    Sicardy, Bruno; Widemann, Thomas; Lellouch, Emmanuel; Veillet, Christian; Colas, Francois; Roques, Francoise; Beisker, Wolfgang; Kretlow, Mike; Cuillandre, Jean-Charles; Hainaut, Olivier

    After the discovery and study of Pluto's tenuous atmosphere in 1985 and 1988 with stellar occultations 14 years were necessary before two other occultations by the planet could be observed on 20 July 2002 and 21 August 2002 from Northern Chile with a portable telescope and from CFHT in Hawaii respectively. These occultations reveal drastric changes in Pluto's nitrogen atmosphere whose pressure increased by a factor two or more since 1988. In spite of an increasing distance to the Sun (and a correlated decrease of solar energy input at Pluto) this increase can be explained by the fact that Pluto's south pole went from permanent darkness to permanent illumination between 1988 and 2002. This might cause the sublimation of the south polar cap and the increase of pressure which could go on till 2015 according to current nitrogen cycle models. Furthermore we detect temperature contrasts between the polar and the equatorial regions probed on Pluto possibly caused by different diurnally averaged insolations at those locations. Finally spikes observed in the light curves reveal a dynamical activity in Pluto's atmosphere.

  18. OCCULT-ORSER complete conversational user-language translator

    NASA Technical Reports Server (NTRS)

    Ramapriyan, H. K.; Young, K.

    1981-01-01

    Translator program (OCCULT) assists non-computer-oriented users in setting up and submitting jobs for complex ORSER system. ORSER is collection of image processing programs for analyzing remotely sensed data. OCCULT is designed for those who would like to use ORSER but cannot justify acquiring and maintaining necessary proficiency in Remote Job Entry Language, Job Control Language, and control-card formats. OCCULT is written in FORTRAN IV and OS Assembler for interactive execution.

  19. [Occult hepatitis B virus infection in chronic hepatitis C].

    PubMed

    Jang, Jae Young; Park, Eui Ju

    2013-09-01

    Occult HBV infection is defined as the presence of HBV DNA in the liver (with or without detectable or undetectable HBV DNA in the serum) of individuals testing negative for HBsAg. Studies on occult HBV infection in hepatitis C patients have reported highly variable prevalence, because the prevalence of occult HBV infection varies depending on the hepatitis B risk factors and methodological approaches. The most reliable diagnostic approach for detecting occult HBV detection is through examination of liver DNA extracts. HCV has been suspected to strongly suppress HBV replication up to the point where it may be directly responsible for occult HBV infection development. However, more data are needed to arrive at a definitive conclusion regarding the role of HCV in inducing occult HBV infection. Occult HBV infection in chronic hepatitis C patients is a complex biological entity with possible relevant clinical implications. Influence of occult HBV infection on the clinical outcomes of chronic hepatitis C may be considered negative. However, recent studies have shown that occult HBV infection could be associated with the development of hepatocellular carcinoma and contribute to the worsening of the course of chronic liver disease over time in chronic hepatitis C patients. Nevertheless, the possible role of occult HBV infection in chronic hepatitis C is still unresolved and no firm conclusion has been made up until now. It still remains unclear how occult HBV infection affects the treatment of chronic hepatitis C. Therefore, in order to resolve current controversies and understand the pathogenic role and clinical impacts of occult HBV infection in chronic hepatitis C patients, well-designed clinical studies are needed.

  20. Boundary diffraction wave integrals for diffraction modeling of external occulters.

    PubMed

    Cady, Eric

    2012-07-01

    An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly model these effects. We present a fast method for the calculation of electric fields following an occulter, based on the concept of the boundary diffraction wave: the 2D structure of the occulter is reduced to a 1D edge integral which directly incorporates the occulter shape, and which can be easily adjusted to include changes in occulter position and shape, as well as the effects of sources-such as exoplanets-which arrive off-axis to the occulter. The structure of a typical implementation of the algorithm is included. PMID:22772218

  1. Mammographic density and breast cancer risk in White and African American Women.

    PubMed

    Razzaghi, Hilda; Troester, Melissa A; Gierach, Gretchen L; Olshan, Andrew F; Yankaskas, Bonnie C; Millikan, Robert C

    2012-09-01

    Mammographic density is a strong risk factor for breast cancer, but limited data are available in African American (AA) women. We examined the association between mammographic density and breast cancer risk in AA and white women. Cases (n = 491) and controls (n = 528) were from the Carolina Breast Cancer Study (CBCS) who also had mammograms recorded in the Carolina Mammography Registry (CMR). Mammographic density was reported to CMR using Breast Imaging Reporting and Data System (BI-RADS) categories. Increasing mammographic density was associated with increased breast cancer risk among all women. After adjusting for potential confounders, a monotonically increasing risk of breast cancer was observed between the highest versus the lowest BI-RADS density categories [OR = 2.45, (95 % confidence interval: 0.99, 6.09)]. The association was stronger in whites, with ~40 % higher risk among those with extremely dense breasts compared to those with scattered fibroglandular densities [1.39, (0.75, 2.55)]. In AA women, the same comparison suggested lower risk [0.75, (0.30, 1.91)]. Because age, obesity, and exogenous hormones have strong associations with breast cancer risk, mammographic density, and race in the CBCS, effect measure modification by these factors was considered. Consistent with previous literature, density-associated risk was greatest among those with BMI > 30 and current hormone users (P value = 0.02 and 0.01, respectively). In the CBCS, mammographic density is associated with increased breast cancer risk, with some suggestion of effect measure modification by race, although results were not statistically significant. However, exposures such as BMI and hormone therapy may be important modifiers of this association and merit further investigation.

  2. Mammographic density and breast cancer risk in White and African American Women

    PubMed Central

    Troester, Melissa A.; Gierach, Gretchen L.; Olshan, Andrew F.; Yankaskas, Bonnie C.; Millikan, Robert C.

    2013-01-01

    Mammographic density is a strong risk factor for breast cancer, but limited data are available in African American (AA) women. We examined the association between mammographic density and breast cancer risk in AA and white women. Cases (n = 491) and controls (n = 528) were from the Carolina Breast Cancer Study (CBCS) who also had mammograms recorded in the Carolina Mammography Registry (CMR). Mammographic density was reported to CMR using Breast Imaging Reporting and Data System (BI-RADS) categories. Increasing mammographic density was associated with increased breast cancer risk among all women. After adjusting for potential confounders, a monotonically increasing risk of breast cancer was observed between the highest versus the lowest BI-RADS density categories [OR = 2.45, (95 % confidence interval: 0.99, 6.09)]. The association was stronger in whites, with ~40 % higher risk among those with extremely dense breasts compared to those with scattered fibroglandular densities [1.39, (0.75, 2.55)]. In AA women, the same comparison suggested lower risk [0.75, (0.30, 1.91)]. Because age, obesity, and exogenous hormones have strong associations with breast cancer risk, mammographic density, and race in the CBCS, effect measure modification by these factors was considered. Consistent with previous literature, density-associated risk was greatest among those with BMI > 30 and current hormone users (P value = 0.02 and 0.01, respectively). In the CBCS, mammographic density is associated with increased breast cancer risk, with some suggestion of effect measure modification by race, although results were not statistically significant. However, exposures such as BMI and hormone therapy may be important modifiers of this association and merit further investigation. PMID:22864770

  3. Malignant mesothelioma

    PubMed Central

    Ahmed, Ishtiaq; Ahmed Tipu, Salman; Ishtiaq, Sundas

    2013-01-01

    Malignant Mesothelioma (MM) is a rare but rapidly fatal and aggressive tumor of the pleura and peritoneum with limited knowledge of its natural history. The incidence has increased in the past two decades but still it is a rare tumor. Etiology of all forms of mesothelioma is strongly associated with industrial pollutants, of which asbestos is the principal carcinogen. Mesothelioma is an insidious neoplasm arising from mesothelial surfaces i.e., pleura (65%-70%), peritoneum (30%), tunica vaginalis testis, and pericardium (1%-2%). The diagnosis of peritoneal and Pleural mesothelioma is often delayed, due to a long latent period between onset and symptoms and the common and nonspecific clinical presentation. The definite diagnosis can only be established by diagnostic laparoscopy or open surgery along with biopsy to obtain histological examination and immunocytochemical analysis. Different treatment options are available but Surgery can achieve a complete or incomplete resection and Radical resection is the preferred treatment. Chemotherapy has an important role in palliative treatment. Photodynamic therapy is also an option under trial. Patients who successfully underwent surgical resection had a considerably longer median survival as well as a significantly higher 5-year survival. Source of Data/Study Selection: The data were collected from case reports, cross-sectional studies, Open-label studies and phase –II trials between 1973-2012. Data Extraction: Web sites and other online resources of American college of surgeons, Medline, NCBI and Medscape resource centers were used to extract data. Conclusion: Malignant Mesothelioma (MM) is a rare but rapidly fatal and aggressive tumor with limited knowledge of its natural history. The diagnosis of peritoneal and Pleural mesothelioma is often delayed, so level of index of suspicion must be kept high. PMID:24550969

  4. A new and fast image feature selection method for developing an optimal mammographic mass detection scheme

    PubMed Central

    Tan, Maxine; Pu, Jiantao; Zheng, Bin

    2014-01-01

    Purpose: Selecting optimal features from a large image feature pool remains a major challenge in developing computer-aided detection (CAD) schemes of medical images. The objective of this study is to investigate a new approach to significantly improve efficacy of image feature selection and classifier optimization in developing a CAD scheme of mammographic masses. Methods: An image dataset including 1600 regions of interest (ROIs) in which 800 are positive (depicting malignant masses) and 800 are negative (depicting CAD-generated false positive regions) was used in this study. After segmentation of each suspicious lesion by a multilayer topographic region growth algorithm, 271 features were computed in different feature categories including shape, texture, contrast, isodensity, spiculation, local topological features, as well as the features related to the presence and location of fat and calcifications. Besides computing features from the original images, the authors also computed new texture features from the dilated lesion segments. In order to select optimal features from this initial feature pool and build a highly performing classifier, the authors examined and compared four feature selection methods to optimize an artificial neural network (ANN) based classifier, namely: (1) Phased Searching with NEAT in a Time-Scaled Framework, (2) A sequential floating forward selection (SFFS) method, (3) A genetic algorithm (GA), and (4) A sequential forward selection (SFS) method. Performances of the four approaches were assessed using a tenfold cross validation method. Results: Among these four methods, SFFS has highest efficacy, which takes 3%–5% of computational time as compared to GA approach, and yields the highest performance level with the area under a receiver operating characteristic curve (AUC) = 0.864 ± 0.034. The results also demonstrated that except using GA, including the new texture features computed from the dilated mass segments improved the AUC

  5. New perspectives in occult hepatitis C virus infection.

    PubMed

    Carreño, Vicente; Bartolomé, Javier; Castillo, Inmaculada; Quiroga, Juan Antonio

    2012-06-21

    Occult hepatitis C virus (HCV) infection, defined as the presence of HCV RNA in liver and in peripheral blood mononuclear cells (PBMCs) in the absence of detectable viral RNA in serum by standard assays, can be found in anti-HCV positive patients with normal serum levels of liver enzymes and in anti-HCV negative patients with persistently elevated liver enzymes of unknown etiology. Occult HCV infection is distributed worldwide and all HCV genotypes seem to be involved in this infection. Occult hepatitis C has been found not only in anti-HCV positive subjects with normal values of liver enzymes or in chronic hepatitis of unknown origin but also in several groups at risk for HCV infection such as hemodialysis patients or family members of patients with occult HCV. This occult infection has been reported also in healthy populations without evidence of liver disease. Occult HCV infection seems to be less aggressive than chronic hepatitis C although patients affected by occult HCV may develop liver cirrhosis and even hepatocellular carcinoma. Thus, anti-HCV negative patients with occult HCV may benefit from antiviral therapy with pegylated-interferon plus ribavirin. The persistence of very low levels of HCV RNA in serum and in PBMCs, along with the maintenance of specific T-cell responses against HCV-antigens observed during a long-term follow-up of patients with occult hepatitis C, indicate that occult HCV is a persistent infection that is not spontaneously eradicated. This is an updated report on diagnosis, epidemiology and clinical implications of occult HCV with special emphasis on anti-HCV negative cases.

  6. [Malignant hyperthermia].

    PubMed

    Metterlein, T; Schuster, F; Graf, B M; Anetseder, M

    2014-12-01

    Malignant hyperthermia (MH) is a rare hereditary, mostly subclinical myopathy. Trigger substances, such as volatile anesthetic agents and the depolarizing muscle relaxant succinylcholine can induce a potentially fatal metabolic increase in predisposed patients caused by a dysregulation of the myoplasmic calcium (Ca) concentration. Mutations in the dihydropyridine ryanodine receptor complex in combination with the trigger substances are responsible for an uncontrolled release of Ca from the sarcoplasmic reticulum. This leads to activation of the contractile apparatus and a massive increase in cellular energy production. Exhaustion of the cellular energy reserves ultimately results in local muscle cell destruction and subsequent cardiovascular failure. The clinical picture of MH episodes is very variable. Early symptoms are hypoxia, hypercapnia and cardiac arrhythmia whereas the body temperature rise, after which MH is named, often occurs later. Decisive for the course of MH episodes is a timely targeted therapy. Following introduction of the hydantoin derivative dantrolene, the previously high mortality of fulminant MH episodes could be reduced to well under 10 %. An MH predisposition can be detected using the invasive in vitro contracture test (IVCT) or mutation analysis. Few elaborate diagnostic procedures are in the developmental stage. PMID:25384957

  7. The Treatment of the Occult in General Encyclopedias.

    ERIC Educational Resources Information Center

    Sonnenfeld, Gary F.

    This paper is a content analysis of three general encyclopedias, "Encyclopedia Americana" (EA), "Encyclopaedia Brittanica" (EB), and "World Book Encyclopedia" (WBC), which quantifies the treatment of the occult. Entries are selected from each by starting with the article "Occultism" and tracing all cross-references. Cross-references are likewise…

  8. Occultations by Uranus and Neptune - 1991-1999

    NASA Technical Reports Server (NTRS)

    Klemola, Arnold R.; Mink, Douglas J.

    1991-01-01

    The results of a photographic plate search are presented for stars as faint as mv = 14 which may be occulted by Uranus or Neptune or their rings between January 1, 1991 and December 31, 1999. Circumstances for the closest approach of Uranus to 76 stars and Neptune to 18 stars are presented. Occultations by Neptune's ring 'arcs' are predicted in 1992, 1997, and 1999.

  9. Impact of D-Dimer for Prediction of Incident Occult Cancer in Patients with Unprovoked Venous Thromboembolism

    PubMed Central

    Han, Donghee; ó Hartaigh, Bríain; Lee, Ji Hyun; Cho, In-Jeong; Shim, Chi Young; Chang, Hyuk-Jae; Hong, Geu-Ru; Ha, Jong-Won; Chung, Namsik

    2016-01-01

    Background Unprovoked venous thromboembolism (VTE) is related to a higher incidence of occult cancer. D-dimer is clinically used for screening VTE, and has often been shown to be present in patients with malignancy. We explored the predictive value of D-dimer for detecting occult cancer in patients with unprovoked VTE. Methods We retrospectively examined data from 824 patients diagnosed with deep vein thrombosis or pulmonary thromboembolism. Of these, 169 (20.5%) patients diagnosed with unprovoked VTE were selected to participate in this study. D-dimer was categorized into three groups as: <2,000, 2,000–4,000, and >4,000 ng/ml. Cox regression analysis was employed to estimate the odds of occult cancer and metastatic state of cancer according to D-dimer categories. Results During a median 5.3 (interquartile range: 3.4–6.7) years of follow-up, 24 (14%) patients with unprovoked VTE were diagnosed with cancer. Of these patients, 16 (67%) were identified as having been diagnosed with metastatic cancer. Log transformed D-dimer levels were significantly higher in those with occult cancer as compared with patients without diagnosis of occult cancer (3.5±0.5 vs. 3.2±0.5, P-value = 0.009, respectively). D-dimer levels >4,000 ng/ml was independently associated with occult cancer (HR: 4.12, 95% CI: 1.54–11.04, P-value = 0.005) when compared with D-dimer levels <2,000 ng/ml, even after adjusting for age, gender, and type of VTE (e.g., deep vein thrombosis or pulmonary thromboembolism). D-dimer levels >4000 ng/ml were also associated with a higher likelihood of metastatic cancer (HR: 9.55, 95% CI: 2.46–37.17, P-value <0.001). Conclusion Elevated D-dimer concentrations >4000 ng/ml are independently associated with the likelihood of occult cancer among patients with unprovoked VTE. PMID:27073982

  10. Retrieval Algorithms for the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Thompson, Robert E.; Gordley, Larry L.

    2009-01-01

    The Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS) provided high quality measurements of key middle atmosphere constituents, aerosol characteristics, and temperature for 14 years (1991-2005). This report is an outline of the Level 2 retrieval algorithms, and it also describes the great care that was taken in characterizing the instrument prior to launch and throughout its mission life. It represents an historical record of the techniques used to analyze the data and of the steps that must be considered for the development of a similar experiment for future satellite missions.

  11. Mammographic density descriptors of novel phantom images: effect of clustered lumpy backgrounds

    NASA Astrophysics Data System (ADS)

    Li, Yanpeng; Brennan, Patrick C.; Ryan, Elaine

    2014-03-01

    Mammographic breast density (MBD) is a risk factor for breast cancer. Both qualitative and quantitative methods have been used to evaluate MBD. However as it is impossible to measure the actual weight or volume of fibroglandular tissue evident on a mammogram, therefore it is hard to know the true correlation between measured mammographic density and the fibroglandular tissue volume. A phantom system has been developed that represents glandular tissue within an adipose tissue structure. Although a previous study has found strong correlation between the synthesised glandular mass and several image descriptors, it is not known if the correlation is still present when a high level of background noise is introduced. The background noise is required to more realistically simulate clinical image appearance. The aim of this study is to investigate if the correlation between percentage density, integrated density, and standard deviation of mean grey value of the whole phantom and simulated glandular tissue mass is affected by background noise being added to the phantom images. For a set of one hundred phantom mammographic images, clustered lumpy backgrounds were synthesised and superimposed onto phantom images. The correlation between the synthesised glandular mass and the image descriptors were calculated. The results showed the correlation is strong and statistically significant for the above three descriptors with r is 0.7597, 0.8208, and 0.7167 respectively. This indicates these descriptors may be used to assess breast fibroglandular tissue content of the breast using mammographic images.

  12. Radio occultation experiments with INAF-IRA radiotelescopes.

    NASA Astrophysics Data System (ADS)

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.

    The Radio Occultation research program performed at the Medicina and Noto Radioastronomical Stations of the Istituto Nazionale di Astrofisica (INAF) - Istituto di Radioastronomia (IRA) includes observations of spacecraft by satellite and satellite by satellite events. The Lunar Radio Occultation (LRO) part of the program consists in collecting data of the lunar Total Electron Content (TEC), at different limb longitudes and at different time, in order to study long term variation of the Moon's ionosphere. The LRO program started at Medicina in September 2006 with the observation of the European probe SMART-1 during its impact on the lunar soil. It proceeded in 2007 with the observation of the lunar occultations of Saturn and Venus, and with the observation of Mars in 2008. On this occasion the probes Cassini, Venus Express, Mars Express, Mars Reconaissance Orbiter and Mars Odissey were respectively occulted by the moon. On Dec 1st 2008 a Venus lunar occultation occurred. On that occasion we performed the first Italian-VLBI (I-VLBI) tracking experiment by detecting the carrier signals coming from the Venus Express (VEX) spacecraft with both the IRA radiotelescopes together with the Matera antenna of the Italian Space Agency. The second part of the radio occultation program includes the observation of satellite by satellite occultation events, as well as mutual occultations of Jupiter satellites. These events are referred to as mutual phenomena (PHEMU). These observations are aimed to measure the radio flux variation during the occultation and to derive surface spatial characteristics such as Io's hot spots. In this work preliminary results of the Radio Occultation program will be presented.

  13. Novel Associations between Common Breast Cancer Susceptibility Variants and Risk-Predicting Mammographic Density Measures

    PubMed Central

    Stone, Jennifer; Thompson, Deborah J.; dos-Santos-Silva, Isabel; Scott, Christopher; Tamimi, Rulla M.; Lindstrom, Sara; Kraft, Peter; Hazra, Aditi; Li, Jingmei; Eriksson, Louise; Czene, Kamila; Hall, Per; Jensen, Matt; Cunningham, Julie; Olson, Janet E.; Purrington, Kristen; Couch, Fergus J.; Brown, Judith; Leyland, Jean; Warren, Ruth M. L.; Luben, Robert N.; Khaw, Kay-Tee; Smith, Paula; Wareham, Nicholas J.; Jud, Sebastian M.; Heusinger, Katharina; Beckmann, Matthias W.; Douglas, Julie A.; Shah, Kaanan P.; Chan, Heang-Ping; Helvie, Mark A.; Le Marchand, Loic; Kolonel, Laurence N.; Woolcott, Christy; Maskarinec, Gertraud; Haiman, Christopher; Giles, Graham G.; Baglietto, Laura; Krishnan, Kavitha; Southey, Melissa C.; Apicella, Carmel; Andrulis, Irene L.; Knight, Julia A.; Ursin, Giske; Grenaker Alnaes, Grethe I.; Kristensen, Vessela N.; Borresen-Dale, Anne-Lise; Gram, Inger Torhild; Bolla, Manjeet K.; Wang, Qin; Michailidou, Kyriaki; Dennis, Joe; Simard, Jacques; Paroah, Paul; Dunning, Alison M.; Easton, Douglas F.; Fasching, Peter A.; Pankratz, V. Shane; Hopper, John; Vachon, Celine M.

    2015-01-01

    Mammographic density measures adjusted for age and body mass index (BMI) are heritable predictors of breast cancer risk but few mammographic density-associated genetic variants have been identified. Using data for 10,727 women from two international consortia, we estimated associations between 77 common breast cancer susceptibility variants and absolute dense area, percent dense area and absolute non-dense area adjusted for study, age and BMI using mixed linear modeling. We found strong support for established associations between rs10995190 (in the region of ZNF365), rs2046210 (ESR1) and rs3817198 (LSP1) and adjusted absolute and percent dense areas (all p <10−5). Of 41 recently discovered breast cancer susceptibility variants, associations were found between rs1432679 (EBF1), rs17817449 (MIR1972-2: FTO), rs12710696 (2p24.1), and rs3757318 (ESR1) and adjusted absolute and percent dense areas, respectively. There were associations between rs6001930 (MKL1) and both adjusted absolute dense and non-dense areas, and between rs17356907 (NTN4) and adjusted absolute non-dense area. Trends in all but two associations were consistent with those for breast cancer risk. Results suggested that 18% of breast cancer susceptibility variants were associated with at least one mammographic density measure. Genetic variants at multiple loci were associated with both breast cancer risk and the mammographic density measures. Further understanding of the underlying mechanisms at these loci could help identify etiological pathways implicated in how mammographic density predicts breast cancer risk. PMID:25862352

  14. Urinary estrogens and estrogen metabolites and mammographic density in premenopausal women

    PubMed Central

    Bertrand, Kimberly A.; Eliassen, A. Heather; Hankinson, Susan E.; Gierach, Gretchen L.; Xu, Xia; Rosner, Bernard; Ziegler, Regina G.; Tamimi, Rulla M.

    2012-01-01

    Mammographic density is a strong and independent risk factor for breast cancer and is considered an intermediate marker of risk. The major predictors of premenopausal mammographic density, however, have yet to be fully elucidated. To test the hypothesis that urinary estrogen metabolism profiles are associated with mammographic density, we conducted a cross-sectional study among 352 premenopausal women in the Nurses’ Health Study II (NHSII). We measured average percent mammographic density using a computer-assisted method. In addition, we assayed 15 estrogens and estrogen metabolites (jointly termed EM) in luteal phase urine samples. We used multivariable linear regression to quantify the association of average percent density with quartiles of each individual EM as well as the sum of all EM (total EM), EM groups defined by metabolic pathway, and pathway ratios. In multivariable models controlling for body mass index (BMI) and other predictors of breast density, women in the top quartile of total EM had an average percent density 3.4 percentage points higher than women in the bottom quartile (95% confidence interval: −1.1, 8.0; p-trend=0.08). A non-significant positive association was noted for the 2-hydroxylation pathway catechols (breast density was 4.0 percentage points higher in top vs. bottom quartile; p-trend=0.06). In general, we observed no associations with parent estrogens or the 4- or 16-hydroxylation pathways or pathway ratios. These results suggest that urinary luteal estrogen profiles are not strongly associated with premenopausal mammographic density. If these profiles are associated with breast cancer risk, they may not act through influences on breast density. PMID:23053640

  15. Circulating levels of inflammatory markers and mammographic density among postmenopausal women

    PubMed Central

    Reeves, Katherine W.; Weissfeld, Joel L.; Modugno, Francesmary; Diergaarde, Brenda

    2012-01-01

    Purpose Mammographic density is strongly associated with breast cancer risk. Inflammation is involved in breast carcinogenesis, perhaps through effects on mammographic density. We evaluated associations between inflammatory markers interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) and mammographic density among postmenopausal women. Methods Plasma IL-6, TNF-α, and CRP levels were measured in 145 women with benign breast disease (benign controls) and 397 women with a negative screening mammogram (well controls) enrolled in the Mammograms and Masses Study. Associations between the inflammatory markers and mammographic density were evaluated separately for benign and well controls through correlation analyses and linear regressions. Results Age-adjusted mean CRP levels were higher among benign controls (2.07 μg/mL) compared to well controls (1.63 μg/mL; p=0.02), while IL-6 and TNF-α levels were similar between groups. Using linear regression, IL-6, TNF-α, and CRP were not statistically significantly associated with dense breast area within either group. Statistically significant positive associations were observed between all three markers and nondense breast area in both groups; statistically significant negative associations were observed between IL-6 and percent density among benign controls, and between all three markers and percent density among well controls. These associations were all attenuated and non-significant upon adjustment for body mass index. Conclusion IL-6, TNF-α, and CRP levels were not independently associated with dense breast area, nondense breast area, or percent density in this study population. Our results suggest that these inflammatory factors do not impact breast carcinogenesis through independent effects on mammographic density. PMID:21069450

  16. Computerized prediction of breast cancer risk: comparison between the global and local bilateral mammographic tissue asymmetry

    NASA Astrophysics Data System (ADS)

    Wang, Xingwei; Lederman, Dror; Tan, Jun; Wang, Xiao Hui; Zheng, Bin

    2011-03-01

    We have developed and preliminarily tested a new breast cancer risk prediction model based on computerized bilateral mammographic tissue asymmetry. In this study, we investigated and compared the performance difference of our risk prediction model when the bilateral mammographic tissue asymmetrical features were extracted in two different methods namely (1) the entire breast area and (2) the mirror-matched local strips between the left and right breast. A testing dataset including bilateral craniocaudal (CC) view images of 100 negative and 100 positive cases for developing breast abnormalities or cancer was selected from a large and diverse full-field digital mammography (FFDM) image database. To detect bilateral mammographic tissue asymmetry, a set of 20 initial "global" features were extracted from the entire breast areas of two bilateral mammograms in CC view and their differences were computed. Meanwhile, a pool of 16 local histogram-based statistic features was computed from eight mirror-matched strips between the left and right breast. Using a genetic algorithm (GA) to select optimal features, two artificial neural networks (ANN) were built to predict the risk of a test case developing cancer. Using the leave-one-case-out training and testing method, two GAoptimized ANNs yielded the areas under receiver operating characteristic (ROC) curves of 0.754+/-0.024 (using feature differences extracted from the entire breast area) and 0.726+/-0.026 (using the feature differences extracted from 8 pairs of local strips), respectively. The risk prediction model using either ANN is able to detect 58.3% (35/60) of cancer cases 6 to 18 months earlier at 80% specificity level. This study compared two methods to compute bilateral mammographic tissue asymmetry and demonstrated that bilateral mammographic tissue asymmetry was a useful breast cancer risk indicator with high discriminatory power.

  17. Robust estimation of mammographic breast density: a patient-based approach

    NASA Astrophysics Data System (ADS)

    Heese, Harald S.; Erhard, Klaus; Gooßen, Andre; Bulow, Thomas

    2012-02-01

    Breast density has become an established risk indicator for developing breast cancer. Current clinical practice reflects this by grading mammograms patient-wise as entirely fat, scattered fibroglandular, heterogeneously dense, or extremely dense based on visual perception. Existing (semi-) automated methods work on a per-image basis and mimic clinical practice by calculating an area fraction of fibroglandular tissue (mammographic percent density). We suggest a method that follows clinical practice more strictly by segmenting the fibroglandular tissue portion directly from the joint data of all four available mammographic views (cranio-caudal and medio-lateral oblique, left and right), and by subsequently calculating a consistently patient-based mammographic percent density estimate. In particular, each mammographic view is first processed separately to determine a region of interest (ROI) for segmentation into fibroglandular and adipose tissue. ROI determination includes breast outline detection via edge-based methods, peripheral tissue suppression via geometric breast height modeling, and - for medio-lateral oblique views only - pectoral muscle outline detection based on optimizing a three-parameter analytic curve with respect to local appearance. Intensity harmonization based on separately acquired calibration data is performed with respect to compression height and tube voltage to facilitate joint segmentation of available mammographic views. A Gaussian mixture model (GMM) on the joint histogram data with a posteriori calibration guided plausibility correction is finally employed for tissue separation. The proposed method was tested on patient data from 82 subjects. Results show excellent correlation (r = 0.86) to radiologist's grading with deviations ranging between -28%, (q = 0.025) and +16%, (q = 0.975).

  18. Breast Tenderness after Initiation of Conjugated Equine Estrogens and Mammographic Density Change

    PubMed Central

    Crandall, Carolyn J.; Aragaki, Aaron K.; Cauley, Jane A.; McTiernan, Anne; Manson, JoAnn E.; Anderson, Garnet L.; Wactawski-Wende, Jean; Chlebowski, Rowan T.

    2013-01-01

    Background We examined the association between new-onset breast tenderness and change in mammographic density after initiation of conjugated equine estrogens (CEE). Methods We analyzed baseline, year 1, and year 2 data from 695 participants of the Women's Health Initiative Estrogen + Progestin (daily CEE 0.625 mg + medroxyprogesterone acetate 2.5 mg [MPA] or placebo) and Estrogen-Alone (CEE 0.625 mg or placebo) trials who participated in the Mammogram Density Ancillary Study. Using multivariable repeated measures models, we analyzed the association between new-onset breast tenderness (i.e. absence of baseline tenderness and presence of tenderness at year 1 follow-up) and change from baseline in percent mammographic density. Results Active therapy increased the odds of new-onset breast tenderness (CEE + MPA vs. placebo risk ratio [RR] 3.01, 95% confidence interval [95% CI] 1.96-4.62; CEE vs. placebo RR 1.70, 95% CI 1.14-2.53). Among women assigned to CEE + MPA, mean increase in mammographic density was greater among participants reporting new-onset of breast tenderness than among participants without new-onset breast tenderness (11.3% vs. 3.9% at year 1, 9.4% vs. 3.2% at year 2, P < 0.001). Among women assigned to CEE alone, increase in mammographic density at year 1 follow-up was not significantly different in women with new-onset breast tenderness compared to women without new-onset breast tenderness (2.4% vs. 0.6% at year 1, 2.2% vs. 1.0% at year 2, P = 0.30). Conclusions The new-onset of breast tenderness after initiation of CEE + MPA, but not CEE alone, is associated with greater increases in mammographic density. PMID:21979747

  19. Processing GPS Occultation Data To Characterize Atmosphere

    NASA Technical Reports Server (NTRS)

    Hajj, George; Kursinski, Emil; Leroy, Stephen; Lijima, Byron; de la Torre Juarez, Manuel; Romans, Larry; Ao, Chi

    2005-01-01

    GOAS [Global Positioning System (GPS) Occultation Analysis System] is a computer program that accepts signal-occultation data from GPS receivers aboard low-Earth-orbiting satellites and processes the data to characterize the terrestrial atmosphere and, in somewhat less comprehensive fashion, the ionosphere. GOAS is very robust and can be run in an unattended semi-operational processing mode. It features sophisticated retrieval algorithms that utilize the amplitudes and phases of the GPS signals. It incorporates a module that, using an assumed atmospheric refractivity profile, simulates the effects of the retrieval processing system, including the GPS receiver. GOAS utilizes the GIPSY software for precise determination of orbits as needed for calibration. The GOAS output for the Earth s troposphere and mid-to-lower stratosphere consists of high-resolution (<1 km) profiles of density, temperature, pressure, atmospheric refractivity, bending angles of signals, and water-vapor content versus altitude from the Earth s surface to an altitude of 30 km. The GOAS output for the ionosphere consists of electron-density profiles from an altitude of about 50 km to the altitude of a satellite, plus parameters related to the rapidly varying structure of the electron density, particularly in the E layer of the ionosphere.

  20. Halogen Occultation Experiment (HALOE) optical filter characterization

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.

    1989-01-01

    The Halogen Occultation Experiment (HALOE) is a solar occultation experiment that will fly on the Upper Atmosphere Research Satellite to measure mixing ratio profiles of O3, H2O, NO2, NO, CH4, HCl, and HF. The inversion of the HALOE data will be critically dependent on a detailed knowledge of eight optical filters. A filter characterization program was undertaken to measure in-band transmissions, out-of-band transmissions, in-band transmission shifts with temperature, reflectivities, and age stability. Fourier Transform Infrared Spectrometers were used to perform measurements over the spectral interval 400/cm to 6300/cm (25 micrometers to 1.6 micrometers). Very high precision (0.1 percent T) in-band measurements and very high resolution (0.0001 percent T) out-of-band measurements have been made. The measurements revealed several conventional leaks at 0.01 percent transmission and greatly enhanced (1,000) leaks to the 2-element filters when placed in a Fabry-Perot cavity. Filter throughput changes by 5 percent for a 25 C change in filter temperature.

  1. Saturn's shape from Cassini radio occultations

    NASA Astrophysics Data System (ADS)

    Flasar, F.; Schinder, P. J.; French, R. G.; Marouf, E. A.; Kliore, A. J.

    2013-12-01

    We report the shape of Saturn's isobaric surfaces between 0.1 mbar and ~1 bar determined from more than thirty Cassini radio-occultation soundings between 70 S and 60 N. The retrieval of pressure vs. planetary radius requires knowledge of the shape of the atmosphere. To do this, we use the gravitational coefficients given by Jacobson et al. (2006) and the angular velocities at the cloud-top level from the Voyager winds reported by Sanchez-Lavega et al. (2000). To keep the ray-tracing inversions tractable, we assume that the atmosphere is locally axisymmetric and that its angular velocity is a function of the distance from the planetary rotation axis; except for near the equator, the latter is equivalent to assuming that the winds are barotropic. Note that the "barotropic" assumption--which permits the use of a geopotential incorporating both gravity and differential rotation--need only apply in the atmospheric shell probed by the occultations. The retrieved isobaric surfaces show evidence of moderate baroclinicity. For example, the deviations of the 1-bar and 100-mbar surfaces from the geopotential surface assumed in the ray tracing are of order 10-20 km, less than a pressure scale height.

  2. Studies with the Pinhole/Occulter Facility

    NASA Technical Reports Server (NTRS)

    Tandberg-Hanssen, E.; Dabbs, J.; Hudson, H.; Greene, M.

    1983-01-01

    The scientific justifications for high-resolution hard X-ray astronomy are reviewed, and a scheme for making such observations from the Space Shuttle payload bay is presented. High-resolution X-ray observations at photon energies above 10 keV are important for the understanding of the physics of solar flares, coronal disturbances related to flares, and corona fine structure, as well as nonsolar X-ray sources. In order to study these phenomena, concepts have been developed for the Shuttle Pinhole/Occulter Facility (P/OF), an instrument based on the principles of the pinhole camera which will have an angular resolution of 0.2 arc sec. The proposed P/OF configuration consists of four separate telescopes or position-sensitive counters mounted on a detector plane and looking toward the target through separate portions of an aperture mask (occulter plane). The two planes are separated by a self-deployable 50-m boom, which is to be made essentially rigid by direct control of its lowest normal modes.

  3. Development of an online, publicly accessible naive Bayesian decision support tool for mammographic mass lesions based on the American College of Radiology (ACR) BI-RADS lexicon

    PubMed Central

    Benndorf, Matthias; Kotter, Elmar; Langer, Mathias; Herda, Christoph; Wu, Yirong; Burnside, Elizabeth S.

    2015-01-01

    Purpose To develop and validate a decision support tool for mammographic mass lesions based on a standardized descriptor terminology (BI-RADS lexicon) to reduce variability of practice. Materials and Methods We used separate training data (1276 lesions, 138 malignant) and validation data (1177 lesions, 175 malignant). We created naïve Bayes (NB) classifiers from the training data with 10-fold cross validation. Our “inclusive model” comprised BI-RADS categories, BI-RADS descriptors and age as predictive variables, our “descriptor model” comprised BI-RADS descriptors and age. The resulting NB classifiers were applied to the validation data. We evaluated and compared classifier performance with ROC-analysis. Results In the training data, the inclusive model yields an AUC of 0.959, the descriptor model yields an AUC of 0.910 (P<0.001). The inclusive model is superior to the clinical performance (BI-RADS categories alone, P<0.001), the descriptor model performs similarly. When applied to the validation data, the inclusive model yields an AUC of 0.935, the descriptor model yields an AUC of 0.876 (P<0.001). Again, the inclusive model is superior to the clinical performance (P<0.001), the descriptor model performs similarly. Conclusion We consider our classifier a step towards a more uniform interpretation of combinations of BI-RADS descriptors. We provide our classifier at www.ebm-radiology.com/nbmm/index.html. PMID:25576230

  4. Review: Occult hepatitis C virus infection: still remains a controversy.

    PubMed

    Vidimliski, Pavlina Dzekova; Nikolov, Igor; Geshkovska, Nadica Matevska; Dimovski, Aleksandar; Rostaing, Lionel; Sikole, Aleksandar

    2014-09-01

    Occult hepatitis C virus (HCV) infection is characterized by the presence of HCV RNA in the liver cells or peripheral blood mononuclear cells of the patients whose serum samples test negative for HCV RNA, with or without presence of HCV antibodies. The present study reviews the existing literature on the persistence of occult hepatitis C virus infection, with description of the clinical characteristics and methods for identification of occult hepatitis C. Occult hepatitis C virus infection was detected in patients with abnormal results of liver function tests of unknown origin, with HCV antibodies and HCV RNA negativity in serum, and also in patients with spontaneous or treatment-induced recovery from hepatitis C. The viral replication in the liver cells and/or peripheral blood mononuclear cells was present in all clinical presentations of occult hepatitis C. The peripheral blood mononuclear cells represent an extra-hepatic site of HCV replication. The reason why HCV RNA was not detectable in the serum of patients with occult hepatitis C, could be the low number of circulating viral particles not detectable by the diagnostic tests with low sensitivity. It is uncertain whether occult hepatitis C is a different clinical entity or just a form of chronic hepatitis C virus infection. Data accumulated over the last decade demonstrated that an effective approach to the diagnosis of HCV infection would be the implementation of more sensitive HCV RNA diagnostic assays, and also, examination of the presence of viral particles in the cells of the immune system.

  5. Simulation of the Mars Ionosphere Radio Occultation Experiments

    NASA Astrophysics Data System (ADS)

    Hu, X.; Wu, X. C.; Gong, X. Y.; Wang, X.; Xu, Q. C.

    2009-07-01

    The Mars ionosphere radio occultation experiment between the Chinese YH-1 spacecraft and the Russian Phobos-Grunt spacecraft orbiting Mars will be the first satellite to satellite radio occultation experiment in history, which will achieve high quality ionospheric electron density profiles. The technique used in this experiment is analyzed and introduced. Simulations of the radio occultation have been completed. Forward calculations of the radio wave observable for the ionospheric radio occultation events have been done with the 3D ray tracing method and a simple Chapman ionosphere background model. The backward inversion with the forward calculated radio occultation observation data gives reliable and consistent ionospheric electron density profiles, which show the reliability of the simulation algorithms. With the simulation method, the effects of errors from the radio signal phase measurement and the orbit determination of the satellite on the inversion are analyzed in cases. Results show that phase errors of 5% circle have a negligible effect on the daytime ionosphere radio occultation, and lead to an absolute error of less than 4×;10^8 m3 for nighttime electron density profiles. Orbit errors of the satellite mainly pose a systematic rising or descending to the ionosphere height. The above results show that Sino-Russian cooperative Mars ionosphere radio occultation experiments is expected to achieve high quality Mars ionosphere profiles. Their technique regime can be used for the lunar ionosphere exploring.

  6. A Digital Video System for Observing and Recording Occultations

    NASA Astrophysics Data System (ADS)

    Barry, M. A. Tony; Gault, Dave; Pavlov, Hristo; Hanna, William; McEwan, Alistair; Filipović, Miroslav D.

    2015-09-01

    Stellar occultations by asteroids and outer solar system bodies can offer ground based observers with modest telescopes and camera equipment the opportunity to probe the shape, size, atmosphere, and attendant moons or rings of these distant objects. The essential requirements of the camera and recording equipment are: good quantum efficiency and low noise; minimal dead time between images; good horological faithfulness of the image timestamps; robustness of the recording to unexpected failure; and low cost. We describe an occultation observing and recording system which attempts to fulfil these requirements and compare the system with other reported camera and recorder systems. Five systems have been built, deployed, and tested over the past three years, and we report on three representative occultation observations: one being a 9 ± 1.5 s occultation of the trans-Neptunian object 28978 Ixion (m v =15.2) at 3 seconds per frame; one being a 1.51 ± 0.017 s occultation of Deimos, the 12 km diameter satellite of Mars, at 30 frames per second; and one being a 11.04 ± 0.4 s occultation, recorded at 7.5 frames per second, of the main belt asteroid 361 Havnia, representing a low magnitude drop (Δm v = ~0.4) occultation.

  7. Independent predictors of breast malignancy in screen-detected microcalcifications: biopsy results in 2545 cases

    PubMed Central

    Farshid, G; Sullivan, T; Downey, P; Gill, P G; Pieterse, S

    2011-01-01

    Background: Mammographic microcalcifications are associated with many benign lesions, ductal carcinoma in situ (DCIS) and invasive cancer. Careful assessment criteria are required to minimise benign biopsies while optimising cancer diagnosis. We wished to evaluate the assessment outcomes of microcalcifications biopsied in the setting of population-based breast cancer screening. Methods: Between January 1992 and December 2007, cases biopsied in which microcalcifications were the only imaging abnormality were included. Patient demographics, imaging features and final histology were subjected to statistical analysis to determine independent predictors of malignancy. Results: In all, 2545 lesions, with a mean diameter of 21.8 mm (s.d. 23.8 mm) and observed in patients with a mean age of 57.7 years (s.d. 8.4 years), were included. Using the grading system adopted by the RANZCR, the grade was 3 in 47.7% 4 in 28.3% and 5 in 24.0%. After assessment, 1220 lesions (47.9%) were malignant (809 DCIS only, 411 DCIS with invasive cancer) and 1325 (52.1%) were non-malignant, including 122 (4.8%) premalignant lesions (lobular carcinoma in situ, atypical lobular hyperplasia and atypical ductal hyperplasia). Only 30.9% of the DCIS was of low grade. Mammographic extent of microcalcifications >15 mm, imaging grade, their pattern of distribution, presence of a palpable mass and detection after the first screening episode showed significant univariate associations with malignancy. On multivariate modeling imaging grade, mammographic extent of microcalcifications >15 mm, palpable mass and screening episode were retained as independent predictors of malignancy. Radiological grade had the largest effect with lesions of grade 4 and 5 being 2.2 and 3.3 times more likely to be malignant, respectively, than grade 3 lesions. Conclusion: The radiological grading scheme used throughout Australia and parts of Europe is validated as a useful system of stratifying microcalcifications into

  8. The occultation of Kappa Geminorum by Eros. [stellar occultation observed for asteroid size and shape

    NASA Technical Reports Server (NTRS)

    Oleary, B.; Marsden, B. G.; Dragon, R.; Hauser, E.; Mcgrath, M.; Backus, P.; Robkoff, H.

    1976-01-01

    The paper discusses predictions and observations of the occultation of Kappa Gem by (433) Eros on January 24, 1975. Several positive and negative observations made in western New England are described. Local circumstances for the occultation are reconstructed, and the size and shape of Eros are determined analytically as well as graphically. The calculations yield two extremes for the cross section: a circle 23 km in diameter or a somewhat irregular figure 20 km by 6 or 7 km. Arguments based on the expected albedo of the asteroid suggest that the circle should be warped into an ellipse 21 by 13 km or that the irregular figure might be one component of a dumbbell-like profile.

  9. The Research and Education Collaborative Occultation Network: A System for Coordinated TNO Occultation Observations

    NASA Astrophysics Data System (ADS)

    Buie, Marc W.; Keller, John M.

    2016-03-01

    We describe a new system and method for collecting coordinated occultation observations of trans-Neptunian objects (TNOs). Occultations by objects in the outer solar system are more difficult to predict due to their large distance and limited span of the astrometric data used to determine their orbits and positions. This project brings together the research and educational community into a unique citizen-science partnership to overcome the difficulties of observing these distant objects. The goal of the project is to get sizes and shapes for TNOs with diameters larger than 100 km. As a result of the system design it will also serve as a probe for binary systems with spatial separations as small as contact systems. Traditional occultation efforts strive to get a prediction sufficiently good to place mobile ground stations in the shadow track. Our system takes a new approach of setting up a large number of fixed observing stations and letting the shadows come to the network. The nominal spacing of the stations is 50 km so that we ensure two chords at our limiting size. The spread of the network is roughly 2000 km along a roughly north-south line in the western United States. The network contains 56 stations that are committed to the project and we get additional ad hoc support from International Occultation Timing Association members. At our minimum size, two stations will record an event while the other stations will be probing the inner regions for secondary events. Larger objects will get more chords and will allow determination of shape profiles. The stations are almost exclusively sited and associated with schools, usually at the 9-12 grade level. We present a full description of the system we have developed for the continued exploration of the Kuiper Belt.

  10. The occultation of HIP 107302 by Jupiter

    NASA Astrophysics Data System (ADS)

    Christou, A. A.; Beisker, W.; Casas, R.; Schnabel, C.; Massallé, A.; Díaz-Martin, M. C.; Assafin, M.; Braga-Ribas, F.; Eppich, P.; Bath, K.-L.; Tsamis, V.; Tigani, K.; Farmakopoulos, A.; Douvris, A.; Liakos, A.; Eberle, A.; Farago, O.

    2013-08-01

    Aims: Occultations of bright stars by planets provide information on the state of their atmospheres. An occultation of the bright star 45 Capricornii (HIP 107302) by Jupiter occurred on the night of 3/4 August 2009. Methods: The event was observed at multiple sites in Europe, Africa and South America and with instruments ranging in aperture from 0.4 m to 2.2 m. All observations, except one, were carried out in methane absorption bands centred at 0.89 μm and 2.2 μm to minimise the planetary contribution to the measured stellar flux. Following the application of special post-processing techniques, differential photometry was performed. Nearby bright satellites were used as reference sources. Results: Fifteen lightcurves were obtained. The photometric time series for fourteen of these were fitted to a model atmosphere of constant scale height (H). Estimates of H for most lightcurves lie within the range 20-30 km with an inverse-variance weighted mean of 23.6 ± 0.4 km, in good agreement with previous works. A comparison between half-light times at ingress and at egress implies an astrometric offset of 10-15 mas in Jupiter's position relative to the star. Five lightcurves - two for ingress and three for egress - were numerically inverted into profiles of pressure versus temperature. Isothermal, mutually consistent behaviour is observed within the pressure range 3-10 μbar. The inferred temperature of 165 ± 5 K is consistent with, but slightly higher than, that measured by the Galileo Probe at 5° S latitude in 1995 at the same pressure level. Subtraction of isothermal models for nine cases show the presence of at least one, and possibly two, non-isothermal layers a few tens of km below the half-light datum. Their altitudes are similar to those of features previously reported during the occultation of HIP 9369 in 1999. Our temperature estimates are consistent with the expected small magnitude of the perturbation of the atmosphere following the impact event on Jupiter

  11. Occultations by Pluto and Charon - 1990-1999

    NASA Technical Reports Server (NTRS)

    Mink, Douglas J.; Klemola, Arnold R.; Buie, Marc W.

    1991-01-01

    The results of a photographic plate search for stars as faint as V = 16 which may be occulted by Pluto or Charon between January 1, 1990 and December 31, 1999 are presented. Circumstances for the closest approach of Pluto to 32 stars and Charon to 28 stars are presented. Photometric information is given for some of the brightest stars found in a search of the Space Telescope Guide Star Catalog for Pluto occultations. Finding charts from Space Telescope Guide Star plates are provided for some of the best events. The brightest star (V = 12.7) may be occulted by both Pluto and Charon on September 26, 1999.

  12. Scattering and extinction: interpreting hazes in stellar occultation data

    NASA Astrophysics Data System (ADS)

    Bosh, Amanda S.; Levine, Stephen; Sickafoose, Amanda A.; Person, Michael J.

    2016-10-01

    There has been debate concerning interpretation of stellar occultation data and whether those data contain evidence for hazes within Pluto's atmosphere. Multiple layers of haze have been imaged in at Pluto with the New Horizons spacecraft; color-dependent differences in minimum flux from stellar occultations also suggests haze. We look at a purely geometric approach, to evaluate whether it is valid to sidestep details of atmospheric temperature structure and, in an approximate manner, conduct an analysis of the 2015 stellar occultation data that is consistent with the New Horizons imaging results. Support for this work was provided by NASA SSO grant NNX15AJ82G to Lowell Observatory.

  13. CT detection of occult pneumothorax in head trauma

    SciTech Connect

    Tocino, I.M.; Miller, M.H.; Frederick, P.R.; Bahr, A.L.; Thomas, F.

    1984-11-01

    A prospective evaluation for occult pneumothorax was performed in 25 consecutive patients with serious head trauma by combining a limited chest CT examination with the emergency head CT examination. Of 21 pneuomothoraces present in 15 patients, 11 (52%) were found only by chest CT and were not identified clinically or by supine chest radiograph. Because of pending therapeutic measures, chest tubes were placed in nine of the 11 occult pneumothoraces, regardless of the volume. Chest CT proved itself as the most sensitive method for detection of occult pneumothorax, permitting early chest tube placement to prevent transition to a tension pneumothorax during subsequent mechanical ventilation or emergency surgery under general anesthesia.

  14. Bone scanning in the detection of occult fractures

    SciTech Connect

    Batillas, J.; Vasilas, A.; Pizzi, W.F.; Gokcebay, T.

    1981-07-01

    The potential role of bone scanning in the early detection of occult fractures following acute trauma was investigated. Technetium 99m pyrophosphate bone scans were obtained in patients with major clinical findings and negative or equivocal roentgenograms following trauma. Bone scanning facilitated the prompt diagnosis of occult fractures in the hip, knee, wrist, ribs and costochondral junctions, sternum, vertebrae, sacrum, and coccyx. Several illustrative cases are presented. Roentgenographic confirmation occurred following a delay of days to weeks and, in some instances, the roentgenographic findings were subtle and could be easily overlooked. This study demonstrates bone scanning to be invaluable and definitive in the prompt detection of occult fractures.

  15. Amount of stroma is associated with mammographic density and stromal expression of oestrogen receptor in normal breast tissues.

    PubMed

    Gabrielson, Marike; Chiesa, Flaminia; Paulsson, Janna; Strell, Carina; Behmer, Catharina; Rönnow, Katarina; Czene, Kamila; Östman, Arne; Hall, Per

    2016-07-01

    Following female sex and age, mammographic density is considered one of the strongest risk factors for breast cancer. Despite the association between mammographic density and breast cancer risk, little is known about the underlying histology and biological basis of breast density. To better understand the mechanisms behind mammographic density we assessed morphology, proliferation and hormone receptor status in relation to mammographic density in breast tissues from healthy women. Tissues were obtained from 2012-2013 by ultrasound-guided core needle biopsy from 160 women as part of the Karma (Karolinska mammography project for risk prediction for breast cancer) project. Mammograms were collected through routine mammography screening and mammographic density was calculated using STRATUS. The histological composition, epithelial and stromal proliferation status and hormone receptor status were assessed through immunohistochemical staining. Higher mammographic density was significantly associated with a greater proportion of stromal and epithelial tissue and a lower proportion of adipose tissue. Epithelial expression levels of Ki-67, oestrogen receptor (ER) and progesterone receptor (PR) were not associated with mammographic density. Epithelial Ki-67 was associated with a greater proportion of epithelial tissue, and epithelial PR was associated with a greater proportion of stromal and a lower proportion of adipose tissue. Epithelial ER was not associated with any tissues. In contrast, expression of ER in the stroma was significantly associated with a greater proportion of stroma, and negatively associated with the amount of adipose tissue. High mammographic density is associated with higher amount of stroma and epithelium and less amount of fat, but is not associated with a change in epithelial proliferation or receptor status. Increased expressions of both epithelial PR and stromal ER are associated with a greater proportion of stroma, suggesting hormonal involvement

  16. Diagnosis of breast cancer in light microscopic and mammographic images textures using relative entropy via kernel estimation.

    PubMed

    Korkmaz, Sevcan Aytac; Korkmaz, Mehmet Fatih; Poyraz, Mustafa

    2016-04-01

    The aim of this article was to provide early detection of breast cancer by using both mammography and histopathology images of the same patient. When the studies in the literature are examined, it is seen that the mammography and histopathology images of the same patient are not used together for early diagnosis of breast cancer. Mammographic and microscopic images can be limited when using only one of them for the early detection of the breast cancer. Therefore, multi-modality solutions that give more accuracy results than single solutions have been realized in this paper. 3 × 50 microscopic (histopathology) and 3 × 50 mammography image sets have been taken from Firat University Medicine Faculty Pathology and Radiology Laboratories, respectively. Optimum feature space has been obtained by minimum redundancy and maximum relevance via mutual information method applying to the 3 × 50 microscopic and mammography images. Then, probabilistic values of suspicious lesions in the image for selected features have been found by exponential curve fitting. Jensen Shannon, Hellinger, and Triangle measurements have been used for the diagnosis of breast cancer. It has been proved that these measures have been related to each other. Weight values for selected each feature have been found using these measures. These weight values have been used in object function. Afterward, histopathology and mammography images have been classified as normal, malign, and benign utilizing object function. In the result of this classifier, the accuracy of diagnosis of breast cancer has been estimated probabilistically. Furthermore, classifications have been probabilistically visualized on a pie chart. Consequently, the performances of Jensen Shannon, Hellinger, and Triangle measures have been compared with ROC analysis using histopathology and mammography test images. It has been observed that Jensen Shannon measure has higher performance than Hellinger and Triangle measures. Accuracy rates of

  17. Significance analysis of qualitative mammographic features, using linear classifiers, neural networks and support vector machines.

    PubMed

    Mavroforakis, Michael; Georgiou, Harris; Dimitropoulos, Nikos; Cavouras, Dionisis; Theodoridis, Sergios

    2005-04-01

    Advances in modern technologies and computers have enabled digital image processing to become a vital tool in conventional clinical practice, including mammography. However, the core problem of the clinical evaluation of mammographic tumors remains a highly demanding cognitive task. In order for these automated diagnostic systems to perform in levels of sensitivity and specificity similar to that of human experts, it is essential that a robust framework on problem-specific design parameters is formulated. This study is focused on identifying a robust set of clinical features that can be used as the base for designing the input of any computer-aided diagnosis system for automatic mammographic tumor evaluation. A thorough list of clinical features was constructed and the diagnostic value of each feature was verified against current clinical practices by an expert physician. These features were directly or indirectly related to the overall morphological properties of the mammographic tumor or the texture of the fine-scale tissue structures as they appear in the digitized image, while others contained external clinical data of outmost importance, like the patient's age. The entire feature set was used as an annotation list for describing the clinical properties of mammographic tumor cases in a quantitative way, such that subsequent objective analyses were possible. For the purposes of this study, a mammographic image database was created, with complete clinical evaluation descriptions and positive histological verification for each case. All tumors contained in the database were characterized according to the identified clinical features' set and the resulting dataset was used as input for discrimination and diagnostic value analysis for each one of these features. Specifically, several standard methodologies of statistical significance analysis were employed to create feature rankings according to their discriminating power. Moreover, three different classification

  18. Verifying Timestamps of Occultation Observation Systems

    NASA Astrophysics Data System (ADS)

    Barry, M. A. Tony; Gault, Dave; Bolt, Greg; McEwan, Alistair; Filipović, Miroslav D.; White, Graeme L.

    2015-04-01

    We describe an image timestamp verification system to determine the exposure timing characteristics and continuity of images made by an imaging camera and recorder, with reference to Coordinated Universal Time. The original use was to verify the timestamps of stellar occultation recording systems, but the system is applicable to lunar flashes, planetary transits, sprite recording, or any area where reliable timestamps are required. The system offers good temporal resolution (down to 2 ms, referred to Coordinated Universal Time) and provides exposure duration and interframe dead time information. The system uses inexpensive, off-the-shelf components, requires minimal assembly, and requires no high-voltage components or connections. We also describe an application to load fits (and other format) image files, which can decode the verification image timestamp. Source code, wiring diagrams, and built applications are provided to aid the construction and use of the device.

  19. Occult Hepatitis B: Clinical Viewpoint and Management

    PubMed Central

    Zobeiri, Mehdi

    2013-01-01

    Occult HBV infection (OBI) is defined as HBV DNA detection in serum or in the liver by sensitive diagnostic tests in HBsAg-negative patients with or without serologic markers of previous viral exposure. OBI seems to be higher among subjects at high risk for HBV infection and with liver disease. OBI can be both a source of virus contamination in blood and organ donations and the reservoir for full blown hepatitis after reactivation. HBV reactivation depends on viral and host factors but these associations have not been analyzed thoroughly. In OBI, it would be best to prevent HBV reactivation which inhibits the development of hepatitis and subsequent mortality. In diverse cases with insufficient data to recommend routine prophylaxis, early identification of virologic reactivation is essential to start antiviral therapy. For retrieving articles regarding OBI, various databases, including OVID, PubMed, Scopus, and ScienceDirect, were used. PMID:23533738

  20. Halogen occultation experiment intergrated test plan

    NASA Technical Reports Server (NTRS)

    Mauldin, L. E., III; Butterfield, A. J.

    1986-01-01

    The test program plan is presented for the Halogen Occultation Experiment (HALOE) instrument, which is being developed in-house at the Langley Research Center for the Upper Atmosphere Research Satellite (UARS). This comprehensive test program was developed to demonstrate that the HALOE instrument meets its performance requirements and maintains integrity through UARS flight environments. Each component, subsystem, and system level test is described in sufficient detail to allow development of the necessary test setups and test procedures. Additionally, the management system for implementing this test program is given. The HALOE instrument is a gas correlation radiometer that measures vertical distribution of eight upper atmospheric constituents: O3, HC1, HF, NO, CH4, H2O, NO2, and CO2.

  1. Profiling Saturn's rings by radio occultation

    SciTech Connect

    Marouf, E.A.; Tyler, G.L.; Rosen, P.A.

    1986-10-01

    The development of reconstruction algorithms that correct for diffraction effects in radio occultation measurements is described. The reciprocal Fresnel transform relationship between the complex amplitude of the observed coherent signal and the complex microwave transmittance of the rings is derived using the Huygens-Fresnel formulation of the diffraction problem. The effects of the finite data segment width, the uncertainties in the Fresnel scale, systematic phase errors in the kernel of the inverse transform, reference oscillator instabilities, and random noise measurements on the resolution of the reconstructed transmittance are analyzed. Examples of reconstructed opacity profiles for some regions of Saturn's rings derived by applying the reconstruction theory to Voyager 1 at Saturn data are presented. 35 references.

  2. Pluto Stellar Occultation on 2008 Aug 25

    NASA Astrophysics Data System (ADS)

    Buie, Marc W.; Young, L. A.; Young, E. F.; Olkin, C. B.; Terrell, D.; Parker, J. W.; Durda, D.; Stansberry, J. A.; Reitsema, H.; French, R. G.; Shoemaker, K.; Brown, M. E.; Schaller, E. L.; Bauer, J. M.; Young, J. W.; Wasserman, L. H.; Pasachoff, J. M.; Lust, N.; Fernandez, Y. R.; Dellinger, J. A.; Garossino, P. G. A.; Grigsby, B.; Stone, R. P. S.; Dillon, W. G.; Mezzalira, F.; Ryan, E. V.; Ryan, W.; Souza, S. P.; Williams, R.; Sexton, C.

    2009-01-01

    We report on a successful occultation of a star by Pluto that was observable over much of the south and western United States. The centerline was close to WIRO. We will present seven complete lightcurves from Crossley/Lick, WIRO, SBO/CU, Palomar, JPL/TMO, Sierra Stars Obs., and Magdalena Ridge Observatory. We have 2 partial lightcurves from Lowell Obs. and McDonald Obs. where data loss was caused by clouds. There were attempts at the Steward 90", George Observatory, and New Mexico Skies that were clouded out. The UCF station near Orlando was clearly an appulse. A number of other amateurs also succeeded in collecting data. Our presentation will provide a final geometric solution for the event as well as baseline fits to the atmospheric structure. This work was supported by NASA Planetary Astronomy grants NNX08AO626 and NNX08AO50G.

  3. Occult pulmonary lymphangitic carcinomatosis presenting as 'chronic cough' with a normal HRCT chest

    PubMed Central

    Jinnur, Praveen K.; Pannu, Bibek S.; Boland, Jennifer M.; Iyer, Vivek N.

    2016-01-01

    A diagnosis of ‘chronic cough’ (CC) requires the exclusion of sinister pulmonary pathology, including infection and malignancy. We present a patient with a 3 month history of CC who had an extensive workup including a normal high resolution computed tomography of the chest (HRCT) 6 weeks prior to consultation at our center. He subsequently developed constitutional symptoms including weight loss and loss of appetite 5 weeks after initial consultation. A repeat HRCT chest and a subsequent whole body PET scan found that he had developed extensive pulmonary lymphangitic carcinomatosis (PLC) from a colon primary. Treatment of the colon cancer resulted in significant decrease in metastatic disease burden and cough resolution. PLC is a very rare cause of ‘chronic cough’ and incipient/occult PLC presenting with chronic cough and a normal initial HRCT chest has not been previously reported. PMID:26958342

  4. Occult pulmonary lymphangitic carcinomatosis presenting as 'chronic cough' with a normal HRCT chest.

    PubMed

    Jinnur, Praveen K; Pannu, Bibek S; Boland, Jennifer M; Iyer, Vivek N

    2016-03-01

    A diagnosis of 'chronic cough' (CC) requires the exclusion of sinister pulmonary pathology, including infection and malignancy. We present a patient with a 3 month history of CC who had an extensive workup including a normal high resolution computed tomography of the chest (HRCT) 6 weeks prior to consultation at our center. He subsequently developed constitutional symptoms including weight loss and loss of appetite 5 weeks after initial consultation. A repeat HRCT chest and a subsequent whole body PET scan found that he had developed extensive pulmonary lymphangitic carcinomatosis (PLC) from a colon primary. Treatment of the colon cancer resulted in significant decrease in metastatic disease burden and cough resolution. PLC is a very rare cause of 'chronic cough' and incipient/occult PLC presenting with chronic cough and a normal initial HRCT chest has not been previously reported. PMID:26958342

  5. Occultations of stars by solar system objects. V - A photographic search for occultations by selected asteroids in 1984

    NASA Technical Reports Server (NTRS)

    Millis, R. L.; Wasserman, L. H.; Franz, O. G.; Bowell, E.; Klemola, A.

    1984-01-01

    Photographic plates taken with the 0.5-m Carnegie double astrograph have been used to identify upcoming asteroid occultations not found in earlier star catalog searches. Twenty-six occultations involving the minor planets 1 Ceres, 10 Hygiea, 52 Europa, 65 Cybele, 451 Patientia, 511 Davida, and 704 Interamnia were found in this search. Of particular interest is the occultation of BD + 8 deg 471 by 1 Ceres on November 13, 1984, which is predicted to be observable throughout much of Mexico and, perhaps, in the southern United States.

  6. Fecal Occult Blood Test and Fecal Immunochemical Test

    MedlinePlus

    ... Visit Global Sites Search Help? Fecal Occult Blood Test and Fecal Immunochemical Test Share this page: Was this page helpful? Also ... Test Common Questions Ask Us Related Pages The Test How is it used? When is it ordered? ...

  7. Nondimensional Representations for Occulter Design and Performance Evaluation

    NASA Technical Reports Server (NTRS)

    Cady, Eric

    2011-01-01

    An occulter is a spacecraft with a precisely-shaped optical edges which ies in formation with a telescope, blocking light from a star while leaving light from nearby planets una ected. Using linear optimization, occulters can be designed for use with telescopes over a wide range of telescope aperture sizes, science bands, and starlight suppression levels. It can be shown that this optimization depends primarily on a small number of independent nondimensional parameters, which correspond to Fresnel numbers and physical scales and enter the optimization only as constraints. We show how these can be used to span the parameter space of possible optimized occulters; this data set can then be mined to determine occulter sizes for various mission scenarios and sets of engineering constraints.

  8. Pupil-segmented photometry for lunar occultation observation

    NASA Astrophysics Data System (ADS)

    Takato, Naruhisa

    2003-03-01

    Occultation is potentially a powerful tool for high-resolution astronomy. It can reach about a few milli-arcsec (mas) by lunar occultation observation and 0.1 mas by that of main-belt asteroids. Photon noise limits the resolution. If we use large telescope in order to increase the number of photons received by a telescope, the fringe pattern that is projected on the earth is averaged over the pupil and the visibility will decrease. I propose to use pupil-segmented method and its performance for lunar occultation. The optimum subaperture size is 2-4 m for lunar occultation. This method is effective for large (> 8-10m) telescope. We can resolve in 6 mas for 16 mag star in > 3 σ noise level using 8 m telescope.

  9. Treatment Options for Metastatic Squamous Neck Cancer with Occult Primary

    MedlinePlus

    ... Patient Hypopharyngeal Cancer Treatment Laryngeal Cancer Treatment Lip & Oral Cavity Treatment Metastatic Squamous Neck Cancer with Occult Primary ... Nasal Cavity Cancer Treatment Salivary Gland Cancer Treatment Oral Cavity and Oropharyngeal Cancer Prevention Oral Cavity and Oropharyngeal ...

  10. Stages of Metastatic Squamous Neck Cancer with Occult Primary

    MedlinePlus

    ... Patient Hypopharyngeal Cancer Treatment Laryngeal Cancer Treatment Lip & Oral Cavity Treatment Metastatic Squamous Neck Cancer with Occult Primary ... Nasal Cavity Cancer Treatment Salivary Gland Cancer Treatment Oral Cavity and Oropharyngeal Cancer Prevention Oral Cavity and Oropharyngeal ...

  11. Treatment Option Overview (Metastatic Squamous Neck Cancer with Occult Primary)

    MedlinePlus

    ... Patient Hypopharyngeal Cancer Treatment Laryngeal Cancer Treatment Lip & Oral Cavity Treatment Metastatic Squamous Neck Cancer with Occult Primary ... Nasal Cavity Cancer Treatment Salivary Gland Cancer Treatment Oral Cavity and Oropharyngeal Cancer Prevention Oral Cavity and Oropharyngeal ...

  12. Radio occultation based on BeiDou satellite navigation

    NASA Astrophysics Data System (ADS)

    Jiang, Hu; Hu, Haiying; Shen, Xue-min; Gong, Wenbin; Zhang, Yonghe

    2014-11-01

    With the development of GNSS systems, it has become a tendency that radio occultation is used to sense the Earth's atmosphere. By this means, the moisture, temperature, pressure, and total electron content can be derived. Based on the sensing results, more complicated models for atmosphere might come into being. Meteorology well benefits from this technology. As scheduled, the BD satellite navigation system will have a worldwide coverage by the end of 2020. Radio occultation studies in China have been highlighted in the recent decade. More and more feasibilities reports have been published in either domestic or international journals. Herein, some scenarios are proposed to assess the coverage of radio occultation based on two different phases of BD satellite navigation system. Phase one for BD is composed of GEO,IGSO and several MEO satellites. Phase two for BD consists mostly of 24 MEO satellites, some GEO and IGSO satellites. The characteristics of radio occultation based on these two phases are presented respectively.

  13. Sizes, Shapes, and Satellites of Asteroids from Occultations

    NASA Astrophysics Data System (ADS)

    Dunham, David W.; Herald, David; Preston, Steve; Timerson, Brad; Maley, Paul; Frappa, Eric; Hayamizu, Tsutomu; Talbot, John; Poro, Atila

    2016-01-01

    For 40 years, the sizes and shapes of many dozens of asteroids have been determined from observations of asteroidal occultations, and over a thousand high-precision positions of the asteroids relative to stars have been measured. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations.

  14. First Results From The Taiwanese-American Occultation Survey (TAOS)

    SciTech Connect

    Zhang, Z; Bianco, F B; Lehner, M J; Coehlo, N K; Wang, J; Mondal, S; Alcock, C; Axelrod, T; Byun, Y; Chen, W P; Cook, K H; Dave, R; de Pater, I; Porrata, R; Kim, D; King, S; Lee, T; Lin, H; Lissauer, J J; Marshall, S L; Protopapas, P; Rice, J A; Schwamb, M E; Wang, S; Wen, C

    2008-08-22

    Results from the first two years of data from the Taiwanese-American Occultation Survey (TAOS) are presented. Stars have been monitored photometrically at 4 Hz or 5 Hz to search for occultations by small ({approx}3 km) Kuiper Belt Objects (KBOs). No statistically significant events were found, allowing us to present an upper bound to the size distribution of KBOs with diameters 0.5 km < D < 28 km.

  15. Stellar occultations. [for composition and thermal structure of Titan atmosphere

    NASA Technical Reports Server (NTRS)

    Veverka, J.

    1974-01-01

    It is important that future occultations by Titan be predicted well in advance, and imperative that they be observed adequately. Stellar occultations can yield reliable temperature/number density profiles of Titan's upper atmosphere near the density level. The temperature profiles can be used to discriminate between atmospheric compositions having high mean molecular weights, and those having low mean molecular weights. Detection of spikes at several wavelengths with high time resolution gives useful limits on the helium content of the atmosphere.

  16. The rings of Uranus - Occultation profiles from three observatories

    NASA Technical Reports Server (NTRS)

    Elias, J. H.; Frogel, J. A.; French, R. G.; Matthews, K.; Meech, K. J.; Mink, D. J.; Nicholson, P. D.; Sicardy, B.; Liller, W.; Elliot, J. L.

    1983-01-01

    Occultation profiles for the nine confirmed Uranian rings obtained from Las Campanas, the European Southern Observatory, and Cerro Tololo on 15-16 August 1980 are compared. The alpha ring shows a 'double-dip' structure; the eta ring shows a broad and narrow component (similar to Saturn's F ring); and the epsilon ring shows six features that appear in the data from all three observatories. Diffraction fringes appear at the edges of several of the occultation profiles.

  17. [Changes in mammographic features of breast cancer--comparison with previous films].

    PubMed

    Matsunaga, T; Hagiwara, K; Kimura, K; Kusama, M

    1992-11-25

    Mammographic features of 87 breast cancer patients were studied in comparison with their previous survey films. Changes in the mammographic features included microcalicification (28 cases), tumor shadow (35 cases) and intratumorous microcalicifications (6 cases). Seven cases had several extremely faint calcifications on the previous films, and three of six cases with clustered and scattered microcalcifications that extended over an entire breast quadrant had increased in number, density and extent. Eight cases in which clustered microcalcifications had increased in number, density and extent suggested a relationship between the increase in the extent of microcalcifications and length of time between visits. In most cases with tumor shadow, a slight localized increase in mammary gland density, irregular margins and straightened trabeculae were overlooked because of breast density.

  18. A clinicopathologic correlation of mammographic parenchymal patterns and associated risk factors for human mammary carcinoma.

    PubMed

    Bland, K I; Kuhns, J G; Buchanan, J B; Dwyer, P A; Heuser, L F; O'Connor, C A; Gray, L A; Polk, H C

    1982-05-01

    The five-year screening experience for 10,131 asymptomatic women evaluated at the Louisville Breast Cancer Detection Demonstration Project (LBCDDP) disclosed 144 breast carcinomas in 1,209 patients (12%) aged 35 to 74 years in whom 904 biopsies and 305 aspirations were performed. This study included 44,711 high-quality xeromammograms (XM) prospectively classified by the modified Wolfe mammographic parenchymal patterns into low-risk (N(1), P(1)) versus high-risk (P(2), DY) groups, with expansion of the P(2) cohort into three additional categories. Using BMDP computer-program analysis, each XM pattern was collated with 21 nonneoplastic and 18 malignant pathologic variables and commonly associated risk factors. A separate analysis of epithelial proliferative and nonproliferative fibrocystic disease of the breast (FCDB) was performed. The histopathology for each biopsy, with distinction of FCDB and neoplasms, was analyzed with regard to the statistical probability of influencing the XM pattern. An average of 1.05 biopsies per patient were performed in women with findings suggestive of carcinoma at clinical and/or XM examinations. An equal distribution of the N(1), P(1), and P(2) DYXM patterns was observed in the 10,131 screenees. Of 8.5% of the screened population having biopsies, 623 were observed to have nonproliferative FCDB and 137, proliferative FCDB. For women 50 years of age or younger, these pathologic variables were seen more frequently in the P(2) DY patterns (p < 0.001), whereas no difference in XM pattern distribution was observed for the screenee 50 years of age or older for proliferative FCDB (p = 0.65). Sixteen percent of the biopsied/aspirated lesions were carcinomas, yielding a biopsy/cancer ratio of 6.25:1. These in situ and invasive neoplasms were more commonly (p < 0.04) observed in 55% of the P(2) (P(2f), P(2n), P(2c)) categories, while 64% of all cancers appeared more frequently in the P(2) DY subgroup (p <0.001), compared with this pattern in the

  19. Direct measurement of mammographic x-ray spectra using a CdZnTe detector.

    PubMed

    Matsumoto, M; Yamamoto, A; Honda, I; Taniguchi, A; Kanamori, H

    2000-07-01

    Our purpose is to directly measure mammographic x-ray spectra with collimators and a low-efficiency CdZnTe detector developed recently and to find out the best fit response function of CdZnTe detector to correct the measured spectra. Photon spectra (target Mo or Rh) produced by a mammographic x-ray unit at 25-32 kV and 240 mAs (= 3 times of 80 mAs) and transmitted through 0.03 mm Mo or 0.025 mm Rh filter and object (0.1 mm Al to 0.8 mm Al phantoms) have been analyzed. Since detected spectra were distorted by the response of CdZnTe detector and did not present the true photon spectra, the correction was applied by the stripping procedure. The response function of detector used in this procedure has been determined by the evaluation of interactions (K-escape, coherent scattering, and Compton scattering processes) and incomplete charge collection calculated using the Monte Carlo method. We have used Kalpha1, Kalpha2, Kbeta1, Kbeta2 radiations of Cd, Zn, and Te, respectively and have used the weight function for the incomplete charge collection and have considered Compton scattering. The Monte Carlo simulations were continued by changing the important factors (mean path length of hole lambda(h), dead layer of the CZT crystal and weight factor Wq) of incomplete charge collection until the best fit response function was found out. Corrected photon spectra were compared with the mammographic x-ray spectral data of Bureau of Radiological Health (BRH) measured using a Ge detector. Attenuation curves of aluminum for 25-32 kV were calculated from the corrected photon spectra and compared with the attenuation curves measured using an ionization chamber. These results obtained using the CdZnTe detector agreed with the mammographic x-ray spectral data of BRH and attenuation curves obtained by the ionization chamber.

  20. Mammographic screening for breast cancer. Overdiagnosis: an insidious adverse effect of screening.

    PubMed

    2015-07-01

    Mammographic mass screening for breast cancer sometimes detects tumours that would grow so slowly that the women concerned would die from other causes before developing noteworthy symptoms. This "overdiagnosis" unnecessarily exposes women to cancer treatments and their adverse effects. To assess the risk of overdiagnosis during mammographic mass screening for breast cancer, we conducted a review of the literature using the standard Prescrire methodology. The most reliable estimates of overdiagnosis are obtained by deduction, based on data from randomised trials with lengthy post-screening follow-up. A randomised trial in Sweden and two in Canada compared screening versus no screening, and monitored the women for an average of 15 and 17 years after the end of screening. For every 10 000 women who were screened, there were 63 cases of breast cancer overdiagnosis in the Swedish trial and 26 in the Canadian trials, representing about 25% of all cancers diagnosed by screening. This rate of overdiagnosis is probably on the low side, as about 20% of the women in the unscreened control groups had at least one mammogram. Studies of the general female population confirm that mammographic mass screening leads to overdiagnosis, but the results add little to those of randomised trials. In 2015, the most reliable estimate is that at least 25% of breast cancers detected by screening mammography are overdiagnosed. In France, at least 19 breast cancers would be overdiagnosed for every 1000 women screened during a 20-year period, corresponding to a total of about 3800 overdiagnosed cancers for each year of mass screening. Women must be informed of the risk of overdiagnosis and its consequences in terms of unnecessary treatment, along with other factors influencing the harm-benefit balance. See page 190 for our proposals on how to inform women wondering whether or not to undergo mammographic screening. PMID:26240891

  1. Ethnic Differences in Mammographic Densities: An Asian Cross-Sectional Study

    PubMed Central

    Mariapun, Shivaani; Li, Jingmei; Yip, Cheng Har; Taib, Nur Aishah Mohd; Teo, Soo-Hwang

    2015-01-01

    Background Mammographic density is a strong risk factor for breast cancer and is highly variable, but, to date, few studies have examined density in Asian women, particularly those in low and middle-income Asian countries where genetic and lifestyle determinants may be significantly different. Methods A total of 1,240 women who attended an opportunistic mammogram screening programme were eligible for analysis. Mammographic density was estimated using a fully-automated thresholding method and differences across ethnic groups were examined using linear regression in 205 randomly selected Chinese women, 138 Malay and 199 Indian women. Results Percent density was significantly higher in Chinese women (28.5%; 95% CI 27.0%, 30.0%) compared to Malay (24.2%; 95% CI 22.5%, 26.0%) and Indian (24.3%; 95% CI 22.8%, 25.7%) women (p<0.001), after adjustment for age, BMI, menopausal status, parity and age at first full term pregnancy. Correspondingly, adjusted nondense area was significantly lower in Chinese (72.2cm2; 95% CI 67.9cm2, 76.5cm2) women compared to Malay (92.1cm2; 95% CI 86.9cm2, 97.2cm2) and Indian (97.7cm2; 95% CI 93.4cm2, 101.9cm2) women (p<0.001), but dense area did not differ across the three ethnic groups. Conclusions Our study shows that higher percent density and lower nondense area reflect the higher incidence of breast cancer in Chinese compared to Malay and Indian women in Malaysia. Known lifestyle determinants of mammographic density do not fully account for the ethnic variations observed in mammographic density in this Asian cohort. PMID:25659139

  2. Earth Occultation Monitoring with the Fermi Gamma Ray Burst Monitor

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2014-01-01

    Using the Gamma Ray Burst Monitor (GBM) on-board Fermi, we are monitoring the hard X-ray/soft gamma ray sky using the Earth occultation technique (EOT). Each time a source in our catalog is occulted by (or exits occultation by) the Earth, we measure its flux using the change in count rates due to the occultation. Currently we are using CTIME data with 8 energy channels spanning 8 keV to 1 MeV for the GBM NaI detectors for daily monitoring. Light curves, updated daily, are available on our website http://heastro.phys.lsu.edu/gbm. Our software is also capable of performing the Earth occultation monitoring using up to 128 energy bands, or any combination of those bands, using our 128-channel, 4-s CSPEC data. The GBM BGO detectors, sensitive from about 200 keV to 40 keV, can also be used with this technique. In our standard application of the EOT, we use a catalog of sources to drive the measurements. To ensure that our catalog is complete, our team has developed an Earth occultation imaging method. In this talk, I will describe both techniques and the current data products available. I will highlight recent and important results from the GBM EOT, including the current status of our observations of hard X-ray variations in the Crab Nebula.

  3. Possible occultation by Pluto from US East Coast

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2012-06-01

    We have been asked to help disseminate the news of a possible occultation by Pluto visible to observers on the US East coast. Although the AAVSO does not ordinarily issue announcements of upcoming occultations, in this case the object is Pluto and the NASA New Horizons mission (http://www.nasa.gov/mission_pages/newhorizons/main/index.html) will be visiting Pluto in 2015. The information below has been supplied by Dr. Leslie Young (Southwest Research Institute), who is coordinating this observing campaign on Pluto. Dr. Young is also Deputy Project Scientist for the New Horizons mission. ALERT: Possible Pluto occultation Wednesday night (2012/06/14 03:28 UT) from US East coast. CONTACT: Leslie Young (layoung@boulder.swri.edu; work: 303-546-6057; skype: drpluto). Also see our planning pages in progress at http://wiki.boulder.swri.edu/mediawiki/index.php/2012-06-14_Pluto_occultation. Pluto's thin, nitrogen atmosphere is in vapor-pressure equilibrium with the surface ice, and changes seasonally. We've seen it double since 1988, and now we measure its pressure once or twice a year. The technique we use is stellar occultation, when a star passes behind Pluto's atmosphere. The atmosphere defocuses the starlight. By the timing of the fading of the star, we measure the pressure and temperature in Pluto's atmosphere at ~10 km resolution. MORE INFORMATION: See http://wiki.boulder.swri.edu/mediawiki/index.php/2012-06-14_Pluto_occultation.

  4. Textural classification of mammographic parenchymal patterns with the SONNET Selforganizing neural network.

    PubMed

    Howard, Daniel; Roberts, Simon C; Ryan, Conor; Brezulianu, Adrian

    2008-01-01

    In nationwide mammography screening, thousands of mammography examinations must be processed. Each consists of two standard views of each breast, and each mammogram must be visually examined by an experienced radiologist to assess it for any anomalies. The ability to detect an anomaly in mammographic texture is important to successful outcomes in mammography screening and, in this study, a large number of mammograms were digitized with a highly accurate scanner; and textural features were derived from the mammograms as input data to a SONNET selforganizing neural network. The paper discusses how SONNET was used to produce a taxonomic organization of the mammography archive in an unsupervised manner. This process is subject to certain choices of SONNET parameters, in these numerical experiments using the craniocaudal view, and typically produced O(10), for example, 39 mammogram classes, by analysis of features from O(10(3)) mammogram images. The mammogram taxonomy captured typical subtleties to discriminate mammograms, and it is submitted that this may be exploited to aid the detection of mammographic anomalies, for example, by acting as a preprocessing stage to simplify the task for a computational detection scheme, or by ordering mammography examinations by mammogram taxonomic class prior to screening in order to encourage more successful visual examination during screening. The resulting taxonomy may help train screening radiologists and conceivably help to settle legal cases concerning a mammography screening examination because the taxonomy can reveal the frequency of mammographic patterns in a population. PMID:18670608

  5. Textural Classification of Mammographic Parenchymal Patterns with the SONNET Selforganizing Neural Network

    PubMed Central

    Howard, Daniel; Roberts, Simon C.; Ryan, Conor; Brezulianu, Adrian

    2008-01-01

    In nationwide mammography screening, thousands of mammography examinations must be processed. Each consists of two standard views of each breast, and each mammogram must be visually examined by an experienced radiologist to assess it for any anomalies. The ability to detect an anomaly in mammographic texture is important to successful outcomes in mammography screening and, in this study, a large number of mammograms were digitized with a highly accurate scanner; and textural features were derived from the mammograms as input data to a SONNET selforganizing neural network. The paper discusses how SONNET was used to produce a taxonomic organization of the mammography archive in an unsupervised manner. This process is subject to certain choices of SONNET parameters, in these numerical experiments using the craniocaudal view, and typically produced O(10), for example, 39 mammogram classes, by analysis of features from O(103) mammogram images. The mammogram taxonomy captured typical subtleties to discriminate mammograms, and it is submitted that this may be exploited to aid the detection of mammographic anomalies, for example, by acting as a preprocessing stage to simplify the task for a computational detection scheme, or by ordering mammography examinations by mammogram taxonomic class prior to screening in order to encourage more successful visual examination during screening. The resulting taxonomy may help train screening radiologists and conceivably help to settle legal cases concerning a mammography screening examination because the taxonomy can reveal the frequency of mammographic patterns in a population. PMID:18670608

  6. A novel phantom system facilitating better descriptors of density within mammographic images

    NASA Astrophysics Data System (ADS)

    Li, Yanpeng; Brennan, Patrick C.; Nickson, Carolyn; Pietrzyk, Mariusz W.; Al Mousa, Dana; Ryan, Elaine

    2013-03-01

    High mammographic density is a risk factor for breast cancer. As it is impossible to measure actual weight or volume of fibroglandular tissue evident within a mammogram, it is hard to know the correlation between measured mammographic density and the actual fibroglandular tissue volume. The aim of this study is to develop a phantom that represents glandular tissue within an adipose tissue structure so that correlations between image feature descriptors and the synthesised glandular structure can be accurately quantified. In this phantom study, ten different weights of fine steel wool were put into gelatine to simulate breast structure. Image feature descriptors are investigated for both the whole phantom image and the simulated density. Descriptors included actual area and percentage area of density, mean pixel intensity for the whole image and dense area, standard deviation of mean intensity, and integrated pixel density which is the production of area and mean intensity. The results show high level correlation between steel-wool weight and percentage density measured on images (r = 0.8421), and the integrated pixel density of dense area (r = 0.8760). The correlation is significant for mean intensity standard deviation for the whole phantom (r = 0.8043). This phantom study may help identify more accurate descriptors of mammographic density, thus facilitating better assessments of fibroglandular tissue appearances.

  7. Computer-aided diagnosis of mammographic masses using scalable image retrieval.

    PubMed

    Jiang, Menglin; Zhang, Shaoting; Li, Hongsheng; Metaxas, Dimitris N

    2015-02-01

    Computer-aided diagnosis of masses in mammograms is important to the prevention of breast cancer. Many approaches tackle this problem through content-based image retrieval techniques. However, most of them fall short of scalability in the retrieval stage, and their diagnostic accuracy is, therefore, restricted. To overcome this drawback, we propose a scalable method for retrieval and diagnosis of mammographic masses. Specifically, for a query mammographic region of interest (ROI), scale-invariant feature transform (SIFT) features are extracted and searched in a vocabulary tree, which stores all the quantized features of previously diagnosed mammographic ROIs. In addition, to fully exert the discriminative power of SIFT features, contextual information in the vocabulary tree is employed to refine the weights of tree nodes. The retrieved ROIs are then used to determine whether the query ROI contains a mass. The presented method has excellent scalability due to the low spatial-temporal cost of vocabulary tree. Extensive experiments are conducted on a large dataset of 11 553 ROIs extracted from the digital database for screening mammography, which demonstrate the accuracy and scalability of our approach. PMID:25361497

  8. International Consortium on Mammographic Density: Methodology and population diversity captured across 22 countries.

    PubMed

    McCormack, Valerie A; Burton, Anya; dos-Santos-Silva, Isabel; Hipwell, John H; Dickens, Caroline; Salem, Dorria; Kamal, Rasha; Hartman, Mikael; Lee, Charmaine Pei Ling; Chia, Kee-Seng; Ozmen, Vahit; Aribal, Mustafa Erkin; Flugelman, Anath Arzee; Lajous, Martín; Lopez-Riduara, Ruy; Rice, Megan; Romieu, Isabelle; Ursin, Giske; Qureshi, Samera; Ma, Huiyan; Lee, Eunjung; van Gils, Carla H; Wanders, Johanna O P; Vinayak, Sudhir; Ndumia, Rose; Allen, Steve; Vinnicombe, Sarah; Moss, Sue; Won Lee, Jong; Kim, Jisun; Pereira, Ana; Garmendia, Maria Luisa; Sirous, Reza; Sirous, Mehri; Peplonska, Beata; Bukowska, Agnieszka; Tamimi, Rulla M; Bertrand, Kimberly; Nagata, Chisato; Kwong, Ava; Vachon, Celine; Scott, Christopher; Perez-Gomez, Beatriz; Pollan, Marina; Maskarinec, Gertraud; Giles, Graham; Hopper, John; Stone, Jennifer; Rajaram, Nadia; Teo, Soo-Hwang; Mariapun, Shivaani; Yaffe, Martin J; Schüz, Joachim; Chiarelli, Anna M; Linton, Linda; Boyd, Norman F

    2016-02-01

    Mammographic density (MD) is a quantitative trait, measurable in all women, and is among the strongest markers of breast cancer risk. The population-based epidemiology of MD has revealed genetic, lifestyle and societal/environmental determinants, but studies have largely been conducted in women with similar westernized lifestyles living in countries with high breast cancer incidence rates. To benefit from the heterogeneity in risk factors and their combinations worldwide, we created an International Consortium on Mammographic Density (ICMD) to pool individual-level epidemiological and MD data from general population studies worldwide. ICMD aims to characterize determinants of MD more precisely, and to evaluate whether they are consistent across populations worldwide. We included 11755 women, from 27 studies in 22 countries, on whom individual-level risk factor data were pooled and original mammographic images were re-read for ICMD to obtain standardized comparable MD data. In the present article, we present (i) the rationale for this consortium; (ii) characteristics of the studies and women included; and (iii) study methodology to obtain comparable MD data from original re-read films. We also highlight the risk factor heterogeneity captured by such an effort and, thus, the unique insight the pooled study promises to offer through wider exposure ranges, different confounding structures and enhanced power for sub-group analyses. PMID:26724463

  9. CdZnTe detector in mammographic x-ray spectroscopy.

    PubMed

    Miyajima, Satoshi; Imagawa, Kotaro

    2002-11-21

    A CdZnTe (CZT) detector was utilized in mammographic x-ray spectroscopy under clinical conditions. First, the detector response was investigated using y-rays from 241Am. The escape of secondary (Compton scattered and K fluorescent) x-rays and tailing due to carrier trapping were minor in the mammographic energy range. In addition, the transmission of primary x-rays was minimal from the results calculated using the mass attenuation coefficients of CZT. Therefore, spectral distortion in this energy range was expected to be negligible. Secondly, x-ray spectroscopy was carried out with the CZT detector. The measured spectra were in good agreement with the spectra obtained with the Compton-scatter method with a high-purity germanium detector. Moreover, the half-value layers (HVLs) calculated from the CZT spectra were consistent with the HVLs measured with an ionization chamber. The results indicate that a CZT detector can be utilized in mammographic x-ray spectroscopy without any corrections.

  10. CdZnTe detector in mammographic x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Miyajima, Satoshi; Imagawa, Kotaro

    2002-11-01

    A CdZnTe (CZT) detector was utilized in mammographic x-ray spectroscopy under clinical conditions. First, the detector response was investigated using γ-rays from 241Am. The escape of secondary (Compton scattered and K fluorescent) x-rays and tailing due to carrier trapping were minor in the mammographic energy range. In addition, the transmission of primary x-rays was minimal from the results calculated using the mass attenuation coefficients of CZT. Therefore, spectral distortion in this energy range was expected to be negligible. Secondly, x-ray spectroscopy was carried out with the CZT detector. The measured spectra were in good agreement with the spectra obtained with the Compton-scatter method with a high-purity germanium detector. Moreover, the half-value layers (HVLs) calculated from the CZT spectra were consistent with the HVLs measured with an ionization chamber. The results indicate that a CZT detector can be utilized in mammographic x-ray spectroscopy without any corrections.

  11. International Consortium on Mammographic Density: Methodology and population diversity captured across 22 countries.

    PubMed

    McCormack, Valerie A; Burton, Anya; dos-Santos-Silva, Isabel; Hipwell, John H; Dickens, Caroline; Salem, Dorria; Kamal, Rasha; Hartman, Mikael; Lee, Charmaine Pei Ling; Chia, Kee-Seng; Ozmen, Vahit; Aribal, Mustafa Erkin; Flugelman, Anath Arzee; Lajous, Martín; Lopez-Riduara, Ruy; Rice, Megan; Romieu, Isabelle; Ursin, Giske; Qureshi, Samera; Ma, Huiyan; Lee, Eunjung; van Gils, Carla H; Wanders, Johanna O P; Vinayak, Sudhir; Ndumia, Rose; Allen, Steve; Vinnicombe, Sarah; Moss, Sue; Won Lee, Jong; Kim, Jisun; Pereira, Ana; Garmendia, Maria Luisa; Sirous, Reza; Sirous, Mehri; Peplonska, Beata; Bukowska, Agnieszka; Tamimi, Rulla M; Bertrand, Kimberly; Nagata, Chisato; Kwong, Ava; Vachon, Celine; Scott, Christopher; Perez-Gomez, Beatriz; Pollan, Marina; Maskarinec, Gertraud; Giles, Graham; Hopper, John; Stone, Jennifer; Rajaram, Nadia; Teo, Soo-Hwang; Mariapun, Shivaani; Yaffe, Martin J; Schüz, Joachim; Chiarelli, Anna M; Linton, Linda; Boyd, Norman F

    2016-02-01

    Mammographic density (MD) is a quantitative trait, measurable in all women, and is among the strongest markers of breast cancer risk. The population-based epidemiology of MD has revealed genetic, lifestyle and societal/environmental determinants, but studies have largely been conducted in women with similar westernized lifestyles living in countries with high breast cancer incidence rates. To benefit from the heterogeneity in risk factors and their combinations worldwide, we created an International Consortium on Mammographic Density (ICMD) to pool individual-level epidemiological and MD data from general population studies worldwide. ICMD aims to characterize determinants of MD more precisely, and to evaluate whether they are consistent across populations worldwide. We included 11755 women, from 27 studies in 22 countries, on whom individual-level risk factor data were pooled and original mammographic images were re-read for ICMD to obtain standardized comparable MD data. In the present article, we present (i) the rationale for this consortium; (ii) characteristics of the studies and women included; and (iii) study methodology to obtain comparable MD data from original re-read films. We also highlight the risk factor heterogeneity captured by such an effort and, thus, the unique insight the pooled study promises to offer through wider exposure ranges, different confounding structures and enhanced power for sub-group analyses.

  12. Pediatric Salivary Gland Malignancies.

    PubMed

    Ord, Robert A; Carlson, Eric R

    2016-02-01

    Pediatric malignant salivary gland tumors are extremely rare. The percentage of malignant tumors is higher than that seen in adults, although the outcomes in terms of survival are better in pediatric patients. The mainstay of treatment is surgical excision with negative margins. This article reviews current concepts in demographics, etiology, management, and outcomes of malignant salivary tumors in children.

  13. Occult nodal metastasis in solid carcinomata

    SciTech Connect

    Moloy, P.J.; Nicolson, G.L.

    1987-01-01

    This book contains 23 selections. Some of the titles are: Rationale for radiotherapy in subclinical nodal disease; rationale of chemotherapy for nodal disease: The stabilization of topoisomerase II-DNA complexes as a mechanism of antineoplastic drug action; magnetic resonance imaging of malignant cervical adenopathy; and local and regional immune function in cancer patients.

  14. Sizes, Shapes, and Satellites of Asteroids from Occultations

    NASA Astrophysics Data System (ADS)

    Waring Dunham, David; Herald, David Russell; Preston, Steve; Timerson, Bradley; Maley, Paul; Frappa, Eric; Hayamizu, Tsutomu; Talbot, John; Poro, Atila

    2015-08-01

    For 40 years, the sizes and shapes of dozens of asteroids have been determined from observations of asteroidal occultations. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations.The release of the Hipparcos and Tycho catalogs in 1997, from ESA’s Hipparcos space mission, revolutionized asteroidal occultation work, increasing the routine accuracy of the predictions and the annual number of observations by an order of magnitude. IOTA developed an efficient procedure for predicting the occultations using a combination of new star catalogs, based on Hipparcos and new star catalogs, generated mainly at the U. S. Naval Observatory (USNO), and new observations of asteroids relative to the improved astrometric nets mainly from USNO’s Flagstaff Astrometric Scanning Transit Telescope and JPL’s Table Mountain Observatory. In addition, many IOTA observers now use inexpensive low-light-level video cameras and specially built GPS video time inserters to accurately time the events. This automation has also allowed some observers to deploy multiple remote video stations across occultation paths. Then, one observer can record several “chords” across the asteroid. The cameras are sensitive enough that easily-hidden telescopes, many of which can be packed in standard air travel suitcases, can be used for many of the predicted occultations. IOTA’s network of regional coordinators collect and reduce the observations

  15. Stellar occultation studies of Saturn's upper atmosphere

    NASA Astrophysics Data System (ADS)

    Foust, Jeffrey Alan

    1999-10-01

    The properties of Saturn's upper atmosphere are not well- known despite several spacecraft flybys. However, the region of 1-100 μbar can be studied in detail by observing stellar occultations-when the planet passes in front of a star-from groundbased or Earth-orbiting telescopes. We use data from five such occultations: three observed in 1995 by the Faint Object Spectrograph (FOS) on the Hubble Space Telescope (HST), one observed in 1996 at the NASA Infrared Telescope Facility (IRTF) and one in 1989 observed by a different instrument at the IRTF. The data span latitudes from 52° south to 75° north. We fit isothermal models to each data set and also perform numerical inversions. These analyses show that temperatures in the 1-10 μbar range can vary significantly as a function of season and latitude, ranging from 121 to 160 K, in accordance with radiative transfer models for the atmosphere. We also search for evidence of gravity wave saturation in Saturn's upper atmosphere, as seen in other planetary atmospheres, by analyzing the power spectra of temperature and density data and by studying the temperature lapse rate in the atmosphere. Our analysis is consistent with saturated gravity waves for all data sets, although gravity wave saturation is not the sole explanation for the spectra. We take advantage of the wavelength-resolved HST FOS data to study the composition of Saturn's upper atmosphere. We measured the difference in feature times for data taken at two wavelengths, and use the different refractivities of hydrogen and helium, as a function of wavelength to compute the relative amounts of the two elements in the planet's atmosphere. We find that the helium mass fraction is 0.26 +/- 0.10, higher than that found using Voyager data, but marginally consistent with theoretical models for the evolution of Saturn's atmosphere, although the large error bars on the results make a definitive conclusion problematic. (Copies available exclusively from MIT Libraries, Rm

  16. Diverse Applications of Occultation Data in Ozone Assimilation

    NASA Technical Reports Server (NTRS)

    Markowitz, A.; Uttley, P.

    2005-01-01

    Ozone profiles from solar occultation instruments provide invaluable information that can be used to evaluate the quality of assimilated ozone fields, from case studies to long-term phenomena. Occultation data can also be applied to include physical constraints while developing components of an assimilation system. Conversely, assimilation of occultation data can help in their validation, and it provides a framework for evaluation of the impact of occultation data on constraining global ozone fields within models. We illustrate these diverse applications by a series of examples using the ozone assimilation system at NASA/Goddard. In a case study, low ozone in the lower stratosphere due to transport of air from the Tropics to northern high latitudes that was captured by assimilation of Aura Microwave Limb Sounder (MLS) and Solar Backscatter Ultraviolet (SBUV) data, was found to agree with SAGE III data. For long-term monitoring, the quality of a multi-year SBUV-only assimilation was evaluated using monthly-mean time series of POAM, HALOE, and SAGE I1 data. We found realism in the representation of the annual cycle in ozone and in some aspects of interannual variability. Assimilation of POAM data was shown to improve the representation of lower stratospheric ozone, especially over Antarctica. More recently, we assimilated ILAS II ozone data in order to help in their validation. Solar occultation data are used to estimate parameters in a new model for forecast error variances that is being developed. These examples demonstrate the importance of occultation data for ozone assimilation, and potential of assimilation to increase the impact and the value of occultation data.

  17. Cassini Radio Occultation Results for Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Marouf, E.; French, R.; Rappaport, N.; McGhee, C.; Wong, K.; Thomson, F.

    2005-12-01

    The Cassini spacecraft completed a set of eight radio occultation observations of Saturn's rings during the period May 2 to September 5, 2005. The observation geometry was optimized to provide multiple ring longitude measurements at three radio wavelengths (0.94, 3.6, 13 cm; Ka-, X-, and S-band, respectively). A normal optical depth profile, a phase shift profile, as well as spectrogram of the near-forward scattered signal are constructed at each observation longitude and wavelength. High spatial resolution X-band optical depth profiles (up to 400 m so far) reveal for the first time detailed structure of Ring B, Saturn's most massive ring feature, as well as structure of many dynamical ring features including density and bending waves driven by exterior satellites, wakes due to embedded satellites, ring gaps, narrow eccentric gap-embedded ringlets, sharp ring edges, among others. Remarkable variability of ring structure with longitude is observed, including prominent asymmetry in Ring A. The Ka/X/S optical depth observations are used to characterize variability in the abundance of particle sizes that populate observed structure over the millimeters to centimeters radius range. Combined, the Ka/X/S optical depth and spectrograms of the near-forward scattered signal provide complementary information about the abundance of the meters size particles and their spatial distribution, including potential crowding, clustering, and preferred orientations.

  18. The occultation of 28 SGR by Titan

    NASA Astrophysics Data System (ADS)

    Hubbard, W. B.; Sicardy, B.; Miles, R.; Hollis, A. J.; Forrest, R. W.; Nicolson, I. K. M.; Appleby, G.; Beisker, W.; Bittner, C.; Bode, H.-J.; Bruns, M.; Denzau, H.; Nezel, M.; Riedel, E.; Struckmann, H.; Arlot, J. E.; Roques, F.; Sevre, F.; Thuillot, W.; Hoffmann, M.; Geyer, E. H.; Buil, C.; Colas, F.; Lecacheux, J.; Klotz, A.; Thouvenot, E.; Vidal, J. L.; Carreira, E.; Rossi, F.; Blanco, C.; Cristaldi, S.; Nevo, Y.; Reitsema, H. J.; Brosch, N.; Cernis, K.; Zdanavicius, K.; Wasserman, L. H.; Hunten, D. M.; Gautier, D.; Lellouch, E.; Yelle, R. V.; Rizk, B.; Flasar, F. M.; Porco, C. C.; Toublanc, D.; Corugedo, G.

    1993-03-01

    We present a comprehensive analysis of data obtained during the 1989 July 3 occultation of 28 Sgr by Titan. The data set includes 23 lightcurves from 15 separate stations, spanning wavelengths from 0.36 to 0.89 micron. A detailed model of the structure of Titan's atmosphere in the altitude range 250 to 450 km is developed, giving the distribution of temperature, pressure, haze optical depth, and zonal wind velocity as a function of altitude and latitude. Haze layers detected in Titan's stratosphere are about one scale height higher than inferred from Voyager data, and show a wavelength dependence indicative of particle sizes on the order of 0.1 micron. A marked north-south dichotomy in haze density is observed with a transition to lower density south of about -20 deg latitude. Zonal wind speeds are inferred from global distortions from spherical symmetry and are of the order of 100 m/s with significant increase toward higher latitudes. Titan's high atmosphere shows substantial axial symmetry; the position angle of the symmetry axis is equal to the position angle of Saturn's spin axis to within about 1 deg.

  19. Occult hepatitis B virus and hepatocellular carcinoma.

    PubMed

    Pollicino, Teresa; Saitta, Carlo

    2014-05-28

    Occult hepatitis B virus (HBV) infection (OBI) is a challenging pathobiological and clinical issue that has been widely debated for several decades. By definition, OBI is characterized by the persistence of HBV DNA in the liver tissue (and in some cases also in the serum) in the absence of circulating HBV surface antigen (HBsAg). Many epidemiological and molecular studies have indicated that OBI is an important risk factor for hepatocellular carcinoma (HCC) development. OBI may exert direct pro-oncogenic effects through the activation of the same oncogenic mechanisms that are activated in the course of an HBsAg-positive infection. Indeed, in OBI as in HBV-positive infection, HBV DNA can persist in the hepatocytes both integrated into the host genome as well as free episome, and may maintain the capacity to produce proteins-mainly X protein and truncated preS-S protein - provided with potential transforming properties. Furthermore, OBI may indirectly favor HCC development. It has been shown that the persistence of very low viral replicative activity during OBI may induce mild liver necro-inflammation continuing for life, and substantial clinical evidence indicates that OBI can accelerate the progression of liver disease towards cirrhosis that is considered the most important risk factor for HCC development.

  20. Not all occult papillary carcinomas are minimal

    SciTech Connect

    Allo, M.D.; Christianson, W.; Koivunen, D.

    1988-12-01

    Occult papillary carcinomas are characterized as small papillary tumors of less than 1.5 cm in maximum diameter, with or without bulky metastatic deposits in cervical nodes. The primary lesion is usually not palpable, and although the clinical behavior usually follows a benign course, tumors with unfavorable histologic features (invasiveness, multifocality) or extrathyroidal disease or a combination of both may not do so. In this report six cases are presented to illustrate this entity. No patient had a history of irradiation to the head or neck. All had primary lesions smaller than 1.5 cm. None had a palpable nodule or abnormal thyroid scan results, and the diagnosis of thyroid cancer was based on cervical lymph node or lung biopsy specimens, which revealed papillary thyroid cancer. All of the patients underwent total or near-total thyroidectomies and were found to have small, invasive papillary lesions with additional metastases to cervical nodes noted at the time of thyroidectomy. Adjunctive treatment consisted of a 5 mCi iodine-131 scan, ablative iodine-131 therapy, and suppression with L-thyroxine. Although distant metastasis to lung or other organs is uncommon and the mortality rate is low (as in larger papillary cancers), these invasive lesions--despite their small size--have a high propensity for recurrence and should be considered to behave more like encapsulated papillary tumors with extrathyroidal extension than like their small, unencapsulated intrathyroidal counterparts.

  1. Gravity wave detection by GPS radio occultations

    NASA Astrophysics Data System (ADS)

    Schmidt, Torsten; Arras, Christina; De la Torre, Alejandro; Alexander, Peter; Llamedo, Pablo

    2016-07-01

    Gravity waves (GWs) play an important role for the general atmospheric circulation due to the related transport of energy and momentum between different regions of the atmosphere. The momentum mostly generated in the troposphere is transported to upper atmospheric levels where GWs break or dissipate and transfer their momentum to the background wind (GW drag). The deposit of GW momentum can occur in the complete altitude range from the upper troposphere-stratosphere, the mesosphere, and even in the thermosphere. A global observation of GW parameters (e.g. potential energy and vertical flux of absolute horizontal momentum) is only possible with satellite data. The radio occultation (RO) technique uses GPS signals received aboard low Earth orbiting satellites for atmospheric limb sounding. Atmospheric temperature profiles in the troposphere/stratosphere and ionospheric electron densities are derived with high vertical resolution. The GPS RO technique is sensitive to GWs with small ratios of vertical to horizontal wavelengths. In this presentation we give an overview about the derivation of GW parameters from RO temperature profiles, review some results of GW detection with RO data, and discuss the limitations of the RO technique. The focus of the presented results is (1) global GW activity in the upper troposphere and lower stratosphere for different seasons, (2) influence of the topography on GW activity from the troposphere to the ionosphere in the Andean region of South America, and (3) the variation of ionospheric sporadic E layers.

  2. Starshade Design for Occulter Based Exoplanet Missions

    NASA Technical Reports Server (NTRS)

    Thomson, Mark W.; Lisman, P. Douglas; Helms, Richard; Walkemeyer, Phil; Kissil, Andrew; Polanco, Otto; Lee, Siu-Chun

    2010-01-01

    We present a lightweight starshade design that delivers the requisite profile figure accuracy with a compact stowed volume that permits launching both the occulter system (starshade and spacecraft) and a 1 to 2m-class telescope system on a single existing launch vehicle. Optimal figure stability is achieved with a very stiff and mass-efficient deployable structure design that has a novel configuration. The reference design is matched to a 1.1m telescope and consists of a 15m diameter inner disc and 24 flower-like petals with 7.5m length. The total tip-to-tip diameter of 30m provides an inner working angle of 75 mas. The design is scalable to accommodate larger telescopes and several options have been assessed. A proof of concept petal is now in production at JPL for deployment demonstrations and as a testbed for developing additional elements of the design. Future plans include developing breadboard and prototype hardware of increasing fidelity for use in demonstrating critical performance capabilities such as deployed optical edge profile figure tolerances and stability thereof.

  3. Diagnose of occult bronchial foreign body

    PubMed Central

    Wang, Lan; Pudasaini, Bigyan; Wang, Xue-Fen

    2016-01-01

    Abstract Background: Occult bronchial foreign body can be very difficult to diagnose early in an adult patient without acute symptoms. This report describes a rare case of undetected Chinese medicine “Coptis chinensis” aspiration for 10 long years. Methods: A case was reported that a female patient complained of a 10-year history of productive cough. A battery of tests were given to confirm the diagnosis. Results: Chest computed tomography (CT) showed extensive bronchiectasis and multiple nodules, along with stenosis of left lower lobar bronchus. An extensive solid lesion with surrounding inflammatory granulation tissue was seen on her first bronchoscopy and biopsy revealed chronic mucosal inflammation. A neglected history of Coptis chinensis regularly kept in-mouth while sleeping for the last 10 years in this patient provided clues for a final diagnosis. Confirmatory diagnosis of bilateral tracheobronchial foreign bodies caused by recurrent inhalation of Coptis chinensis was made by a second bronchoscopy. Conclusions: This case clearly demonstrates that a precise medical history is often overlooked. A high index of suspicion, a precise medical history, radiographic features of chronic respiratory symptoms not explained by other conditions were keys to diagnosing this case. PMID:27495017

  4. Estimate of tissue composition in malignant and benign breast lesions by time-domain optical mammography.

    PubMed

    Quarto, Giovanna; Spinelli, Lorenzo; Pifferi, Antonio; Torricelli, Alessandro; Cubeddu, Rinaldo; Abbate, Francesca; Balestreri, Nicola; Menna, Simona; Cassano, Enrico; Taroni, Paola

    2014-10-01

    The optical characterization of malignant and benign breast lesions is presented. Time-resolved transmittance measurements were performed in the 630-1060 nm range by means of a 7-wavelength optical mammograph, providing both imaging and spectroscopy information. A total of 62 lesions were analyzed, including 33 malignant and 29 benign lesions. The characterization of breast lesions was performed applying a perturbation model based on the high-order calculation of the pathlength of photons inside the lesion, which led to the assessment of oxy- and deoxy-hemoglobin, lipids, water and collagen concentrations. Significant variations between tumor and healthy tissue were observed in terms of both absorption properties and constituents concentration. In particular, benign lesions and tumors show a statistically significant discrimination in terms of absorption at several wavelengths and also in terms of oxy-hemoglobin and collagen content.

  5. Estimate of tissue composition in malignant and benign breast lesions by time-domain optical mammography

    PubMed Central

    Quarto, Giovanna; Spinelli, Lorenzo; Pifferi, Antonio; Torricelli, Alessandro; Cubeddu, Rinaldo; Abbate, Francesca; Balestreri, Nicola; Menna, Simona; Cassano, Enrico; Taroni, Paola

    2014-01-01

    The optical characterization of malignant and benign breast lesions is presented. Time-resolved transmittance measurements were performed in the 630-1060 nm range by means of a 7-wavelength optical mammograph, providing both imaging and spectroscopy information. A total of 62 lesions were analyzed, including 33 malignant and 29 benign lesions. The characterization of breast lesions was performed applying a perturbation model based on the high-order calculation of the pathlength of photons inside the lesion, which led to the assessment of oxy- and deoxy-hemoglobin, lipids, water and collagen concentrations. Significant variations between tumor and healthy tissue were observed in terms of both absorption properties and constituents concentration. In particular, benign lesions and tumors show a statistically significant discrimination in terms of absorption at several wavelengths and also in terms of oxy-hemoglobin and collagen content. PMID:25360382

  6. Free-flying Occulters for Use with Space Telescopes

    NASA Astrophysics Data System (ADS)

    Kochte, M.; Schultz, A. B.; Jordan, I.; Hamilton, F.; Bruhweiler, F.; DiSanti, M. A.; Burns, R. D.; Carpenter, K.; Hollis, J. M.; Leitner, J.; Lyon, R. G.; Starin, S.; Fadali, M. S.; Rodrigue, M.; Skelton, D. L.; Hart, H. M.

    2001-12-01

    We summarize a free-flying occulter proposal that was submitted to NASA in response to NRA-01-OSS-04. Free-flying occulters in association with space telescopes have been proposed for nearly four decades to detect and study extrasolar planets. External occulters reduce the magnitude differences between a planet and the host star; light scatter within the telescope is reduced resulting from fewer obstructions and optical surfaces; and any instrument onboard the telescope, including spectrometers, can be used to study extrasolar planets. We conclude with a mission concept for an optimized optical 1-m space telescope with a small external occulter. Both craft could be launched from a single launch vehicle and placed in a 1-AU fall-away orbit or at Earth-Sun L2. Jovian planets around stars within 10 parsecs could be studied, and a search for sub-Jovian planets around the nearest handful of stars could be performed. Approximately 80% of the telescope time would be available for projects not associated with the external occulter such as gravitational lensing and planetary transit surveys.

  7. [Occultism, parapsychology and the esoteric from the perspective of psychopathology].

    PubMed

    Scharfetter, C

    1998-10-01

    The concepts and main themes of occultism, parapsychology and esoterics are set in comparison to religion, spirituality, mysticism. The cultural relativity of these concepts is emphasised. Occultism means dealing with phenomena, processes, and/or powers which are not accessible to "normal perception". The manipulation of such powers is effected via (white, black, grey) magic. Parapsychology, in its popular sense, deals with occult phenomena, whereas scientific parapsychology investigates them empirically. Esoterics is a complex of beliefs within a hermetic tradition about occult processes and about desting after death. Transpersonal psychology deals with these issues while calling them "spiritual". Effects of paranormal experiences and actions on the side of the actor as well as the adept are discussed: personality types, interpersonal effects, crises and psychoses (mediumistic psychoses). The concept of dissociation of subpersonalities (subselves) appears to be a viable perspective to explain these phenomena. In mediumistic psychoses, the splitting of non-ego parts of the psyche leads to a manifestation of schizophrenic symptoms. Dangers for mental health are an ego inflation by self-attribution of "superhuman" power. A personality disposition for parapsychological perception and/or action may be seen in schizotypia and similar near-psychotic "personalities up the border". Adepts of occultism may present with a "false self" in the sense of Winnicott.

  8. Further Optical Verification of Occulter-Based High Contrast Imaging

    NASA Astrophysics Data System (ADS)

    Sirbu, Dan; Kasdin, N. J.; Vanderbei, R. J.

    2013-01-01

    Direct imaging of an Earth-like planet around nearby stars represents a challenge for two primary reasons. First, the intensity ratio between the bright star and its dim Earth-like planetary companion is expected to be approximately ten orders of magnitude and secondly the angular separation to the star is very small. An external occulter is a specially-shaped spacecraft that is flown in formation with a telescope in order to block most of the starlight before it reaches the entrance pupil thereby allowing planetary light outside of the occulter's inner working angle to become visible. At Princeton, we have designed an experimental testbed where we scaled an occulter by maintaining constant Fresnel numbers to fit in the laboratory. We present monochromatic results in the image plane showing contrast better than 10 orders of magnitude obtained using an optimized occulter shape, which is a significant improvement over a baseline case using a circular occulter. We also present a preliminary implementation of an algorithm that uses the Poisson spot formed by out-of-band leaked light to estimate the location of the telescope in the shadow and perform fine alignment during science observations.

  9. Radio Occultation Measurements of Pluto's Atmosphere with New Horizons

    NASA Astrophysics Data System (ADS)

    Hinson, D. P.; Linscott, I.; Tyler, G. L.; Bird, M. K.; Paetzold, M.; Strobel, D. F.; Summers, M. E.; Woods, W. W.; Stern, A.; Weaver, H. A., Jr.; Olkin, C.; Young, L. A.; Ennico Smith, K.; Gladstone, R.; Greathouse, T.; Kammer, J.; Parker, A. H.; Parker, J. W.; Retherford, K. D.; Schindhelm, E.; Singer, K. N.; Steffl, A.; Tsang, C.; Versteeg, M.

    2015-12-01

    The reconnaissance of the Pluto System by New Horizons included radio occultations at both Pluto and Charon. This talk will present the latest results from the Pluto occultation. The REX instrument onboard New Horizons received and recorded uplink signals from two 70-m antennas and two 34-m antennas of the NASA Deep Space Network - each transmitting 20 kW at 4.2-cm wavelength - during a diametric occultation by Pluto. At the time this was written only a short segment of data at occultation entry (193°E, 17°S) was available for analysis. The REX measurements extend unequivocally to the surface, providing the first direct measure of the surface pressure and the temperature structure in Pluto's lower atmosphere. Preliminary analysis yields a surface pressure of about 10 microbars, smaller than expected. Data from occultation exit (16°E, 15°N) are scheduled to arrive on the ground in late August 2015. Those observations will yield an improved estimate of the surface pressure, a second temperature profile, and a measure of the diameter of Pluto with a precision of a few hundred meters.

  10. Crosslink Radio Occultation for the Remote Sensing of Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Mannucci, A. J.; Ao, C. O.; Asmar, S.; Edwards, C. D.; Kahan, D. S.; Paik, M.; Pi, X.; Williamson, W.

    2015-12-01

    Radio occultation utilizing deep space telecommunication signals has been used with great success in the profiling of planetary atmospheres and ionospheres since the 1960s. A shortcoming of this technique, however, is the limited temporal and spatial sampling that it provides. We consider a different approach where radio occultation measurements are taken between two spacecraft orbiting an extra-terrestrial body. Such "crosslink" radio occultations between the Global Positioning System satellites and low-earth orbiting spacecraft have been routinely acquired to provide global observations of the Earth's atmosphere and ionosphere that are used for weather forecast, climate analysis, and space weather applications. The feasibility of applying this concept to other planets has recently been demonstrated for the first time, where crosslink occultation measurements have been acquired between the Mars Odyssey and Mars Reconnaissance Orbiter spacecraft. These measurements leverage the proximity link telecommunication payloads on each orbiter, which are nominally used to provide relay communication and navigation services to Mars landers and rovers. In this presentation, we will describe the Mars crosslink experiments and the corresponding data analysis in detail. In addition, we will discuss how the crosslink occultation concepts can be effectively applied in future space exploration missions.

  11. Rate of occult specimen provenance complications in routine clinical practice.

    PubMed

    Pfeifer, John D; Liu, Jingxia

    2013-01-01

    Occult specimen provenance complications (SPCs), which occur when there is an absence of any direct or indirect indication that a specimen switch or contamination may have occurred, constitute a significant patient safety and medical-legal problem because they can lead to misdiagnosis. However, the rate at which occult SPCs occur is unknown because, by definition, this category of errors is not identified by standard laboratory practices. In this study, we evaluated a data set comprising almost 13,000 prostate biopsies that were prospectively tested for specimen provenance errors as part of routine clinical practice. The frequency of occult type 1 errors (a complete transposition between patients) and type 2 errors (contamination of the patient's tissue with 1 or more unrelated patients) was 0.26% and 0.67%, respectively; every urology practice setting and surgical pathology laboratory type with a representative sample size experienced at least 1 type 1 and 1 type 2 error during the study period. Overall, the mean frequency of SPCs across practice settings was 0.22% for type 1 errors and 1.69% for type 2 errors. The type 1 rate showed no correlation with a surgical pathology laboratory setting or urologic practice group setting; the type 2 rate correlated solely with a surgical pathology laboratory setting. The occult SPC rate in this limited data set provides an estimate of the scope of the problem of potential misdiagnosis as a result of occult specimen provenance errors in routine clinical practice.

  12. Observation and Interpretation of Lunar Occultations. Ph.D. Thesis; [Uranus and beta Capricorni

    NASA Technical Reports Server (NTRS)

    Radick, R. R.

    1978-01-01

    The importance of timings and high resolution astrometry in occultation observations is discussed as well as the occultation process itself. The design and operation of the telescope, photodetector, and data acquisition systems are described. Methods are presented for data analysis and model fitting. Observations of beta Capricorni and Uranus occultations are examined. General conclusions concerning occultation observations are explored and future activities at Prairie Observatory are discussed.

  13. Update on occult hepatitis B virus infection

    PubMed Central

    Makvandi, Manoochehr

    2016-01-01

    The event of mutations in the surface antigen gene of hepatitis B virus (HBV) results in undetectable hepatitis B surface antigen with positive/negative anti-hepatitis B core (anti-HBc) antibody status in serum and this phenomenon is named occult hepatitis B infection (OBI). The presence of anti-HBc antibody in serum is an important key for OBI tracking, although about 20% of OBI cases are negative for anti-HBc antibody. The diagnosis of OBI is mainly based on polymerase chain reaction (PCR) and real-time PCR assays. However, real-time PCR is a more reliable method than PCR. OBI is a great issue for the public health problem and a challenge for the clinical entity worldwide. The persistence of OBI may lead to the development of cirrhosis and hepatocellular carcinoma. With regard to OBI complications, the screening of HBV DNA by the highly sensitive molecular means should be implemented for: (1) patients with a previous history of chronic or acute HBV infection; (2) patients co-infected with hepatitis C virus/human immunodeficiency virus; (3) patients undergoing chemotherapy or anti-CD20 therapy; (4) recipients of organ transplant; (5) blood donors; (6) organ transplant donors; (7) thalassemia and hemophilia patients; (8) health care workers; (9) patients with liver related disease (cryptogenic); (10) hemodialysis patients; (11) patients undergoing lamivudine or interferon therapy; and (12) children in time of HBV vaccination especially in highly endemic areas of HBV. Active HBV vaccination should be implemented for the close relatives of patients who are negative for OBI markers. Thus, the goal of this review is to evaluate the rate of OBI with a focus on status of high risk groups in different regions of the world.

  14. Calculated occultation profiles of Io and the hot spots

    NASA Astrophysics Data System (ADS)

    McEwen, A. S.; Soderblom, L. A.; Matson, D. L.; Johnson, T. V.; Lunine, J. I.

    1986-03-01

    Occultations of Io by other Galilean satellites in 1985 provide a means to locate volcanic hot spots and to model their temperatures. The expected time variations in the integral reflected and emitted radiation of the occultations are computed as a function of wavelength (visual to 8.7 microns). The best current ephemerides were used to calculate the geometry of each event as viewed from earth. Visual reflectances were modeled from global mosaics of Io. Thermal emission from the hot spots was calculated from Voyager 1 IRIS observations and, for regions unobserved by IRIS, from a model based on the distribution of low-albedo features. The occultations may help determine (1) the location and temperature distribution of Loki; (2) the source(s) of excess emission in the region from long 50 deg to 200 deg and (3) the distribution of small, high-temperature sources.

  15. Stellar Occultations from Airborne Platforms: 1988 to 2016

    NASA Astrophysics Data System (ADS)

    Bosh, Amanda S.; Dunham, Edward W.; Zuluaga, Carlos; Levine, Stephen; Person, Michael J.; Van Cleve, Jeffrey E.

    2016-10-01

    Observing a stellar occultation by a solar system body with an airborne telescope requires precise positioning of the observer within the shadow cast onto the Earth. For small bodies like Pluto and Kuiper Belt objects, smaller than the Earth, the challenge is particularly intense, with the accuracy of the astrometric and flight planning determining whether the observation succeeds or fails. From our first airborne occultation by Pluto in 1988 aboard the Kuiper Airborne Observatory (KAO), to our most recent event by Pluto in 2015 aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA), we have refined our astrometric and flight planning systems to the point where we can now place an airborne observer into the small central flash zone. We will discuss the history of airborne observation of occultations while detailing the improvements in the astrometric processes. Support for this work was provided by NASA SSO grant NNX15AJ82G to Lowell Observatory.

  16. TAOS: An Occultation Survey of the Outer Solar System

    NASA Astrophysics Data System (ADS)

    Lehner, M. J.; Alcock, C.; Axelrod, T.; Bianco, F. B.; Byun, Y.-I.; Chen, W. P.; Cook, K. H.; de Pater, I.; Geary, J. C.; Kim, D.-W.; King, S.-K.; Lee, T.; Marshall, S. L.; Norton, T.; Protopapas, P.; Rice, J. A.; Ruiz Reyes, M.; Schwamb, M. E.; Szentgyorgyi, A.; Wang, J.-H.; Wang, S.-Y.; Wen, C.-Y.; Zhang, Z.-W.

    2011-10-01

    The Taiwanese-American Occultation survey (TAOS) operate four small telescopes in central Taiwan to search for occultations by small (∼1 km diameter) Kuiper Belt Objects. The system is fully robotic, requiring human intervention only in the event of hardware failures. However, the status of the system during observations is monitored remotely via smart-phone. A successor survey, the Transneptunian Automated Occultation Survey (TAOS II)1 is currently being constructed. This next generation survey will be more than one hundred times as sensitive as the earlier survey. In my talk I will present the results of TAOS I, discuss the future plans of the survey, and provide a detailed description of the TAOS II project.

  17. The concept of the Pinhole/Occulter Facility

    NASA Technical Reports Server (NTRS)

    Hudson, H. S.

    1986-01-01

    The Pinhole/Occulter Facility is based on a simple idea for obtaining high angular resolution in astronomical X-ray observations, for example for solar flares at energies 10 keV. The scheme uses a coded aperture device (multiple pinhole camera) with a large separation between the aperture encoder and the detector. Such an imaging device can have an angular resolution much better than 1 arc s if desired. A large structure would also make it possible to have a large external occulter, which would have powerful applications, notably for high-sensitivity observations of the corona in EUV and white light. This capability leads to the definition of the Pinhole/Occulter Facility, which combines both X-ray and coronal observations. The present concept is based on a 35-m deployable boom, erected in the cargo bay of the Space Shuttle and pointed in the solar direction by the Instrument Pointing System of Spacelab.

  18. Rheumatic Diseases and Malignancies

    PubMed Central

    BOJINCA, Violeta; JANTA, Iustina

    2012-01-01

    ABSTRACT There are many studies which demonstrate a higher risk for malignancy in patients with rheumatic diseases. There have been a number of possible explanations for the differences in the risk of certain malignancies in patients with rheumatic disease, compared with general population, but a clear mechanism is difficult to identify. Rheumatoid syndromes may be associated with malignancy as paraneoplastic conditions, which can antedate the neoplasm diagnosis. On the other hand, autoimmune rheumatic diseases have a higher risk of malignancy by themselves or because of the immunosuppressant treatments. PMID:23482881

  19. Scintillations during occultations by planets. 1. An approximate theory. [fresnel region

    NASA Technical Reports Server (NTRS)

    Young, A. T.

    1975-01-01

    Scintillations observed during occultations of both stars and spacecraft by planetary atmospheres are discussed theoretically. The effects of severe flattening of the Fresnel zone or source image by defocusing on occultations are presented, along with temporal power spectra. Other topics discussed include atmospheric turbulence, saturation of scintillation, effects of saturation on occultation curves, and some methods for a more accurate determination of atmospheric structure.

  20. High-density lipoprotein-cholesterol, daily estradiol and progesterone, and mammographic density phenotypes in premenopausal women.

    PubMed

    Flote, Vidar G; Frydenberg, Hanne; Ursin, Giske; Iversen, Anita; Fagerland, Morten W; Ellison, Peter T; Wist, Erik A; Egeland, Thore; Wilsgaard, Tom; McTiernan, Anne; Furberg, Anne-Sofie; Thune, Inger

    2015-06-01

    High-density lipoprotein-cholesterol (HDL-C) may influence the proliferation of breast tumor cells, but it is unclear whether low HDL-C levels, alone or in combination with cyclic estrogen and progesterone, are associated with mammographic density, a strong predictor of breast cancer development. Fasting morning serum concentrations of HDL-C were assessed in 202 premenopausal women, 25 to 35 years of age, participating in the Norwegian Energy Balance and Breast Cancer Aspects (EBBA) I study. Estrogen and progesterone were measured both in serum, and daily in saliva, throughout an entire menstrual cycle. Absolute and percent mammographic density was assessed by a computer-assisted method (Madena), from digitized mammograms (days 7-12). Multivariable models were used to study the associations between HDL-C, estrogen and progesterone, and mammographic density phenotypes. We observed a positive association between HDL-C and percent mammographic density after adjustments (P = 0.030). When combining HDL-C, estradiol, and progesterone, we observed among women with low HDL-C (<1.39 mmol/L), a linear association between salivary 17β-estradiol, progesterone, and percent and absolute mammographic density. Furthermore, in women with low HDL-C, each one SD increase of salivary mid-menstrual 17β-estradiol was associated with an OR of 4.12 (95% confidence intervals; CI, 1.30-13.0) of having above-median percent (28.5%), and an OR of 2.5 (95% CI, 1.13-5.50) of having above-median absolute mammographic density (32.4 cm(2)). On the basis of plausible biologic mechanisms linking HDL-C to breast cancer development, our findings suggest a role of HDL-C, alone or in combination with estrogen, in breast cancer development. However, our small hypothesis generating study requires confirmation in larger studies.

  1. Classification of F Ring Features Observed in Cassini UVIS Occultations

    NASA Astrophysics Data System (ADS)

    Meinke, Bonnie K.; Esposito, L. W.; Albers, N.; Sremcevic, M.

    2010-10-01

    The Cassini Ultraviolet Imaging Spectrograph (UVIS) has observed 25 statistically significant F ring features in 91 occultations since July 2004. This work nearly doubles the number of features reported by Esposito et al. (2008). As the number of statistically significant features has grown, it has become useful to classify them for the purposes of cataloging. We define three categories: Moonlet, Core, and Icicle, which classify the shapes of features seen to date in the occultation profiles of the F ring. Two features fall into the Moonlet class. Each is opaque in its occultation, which makes them candidates for solid objects. We classify 17 of the significant observed features as Icicles, which partially block stellar signal for 22 m to just over 3.7 km along the radial expanse of the occultation. The density enhancements responsible for such signal attenuations are likely due to transient clumping of material, evidence that aggregations of material are ubiquitous in the F ring. Finally, the variety of core region shapes displays how even the general shape of the F ring is ever-changing. The core region of the F ring usually has a smooth U-shape to it, but the core region takes the shape of Ws and Vs in some occultation profiles. Our lengthy observing campaign reveals possible states and possible causes of the observed structure through these three feature classes. We discuss the constraints on the dimensions of the physical objects responsible for the observed occultation features. We explore how opacity and shape differences among the observed features may be related to the porosities of aggregates in the F ring. This research was supported by the Cassini Project.

  2. Constraints on Pluto's Hazes from 2-Color Occultation Lightcurves

    NASA Astrophysics Data System (ADS)

    Hartig, Kara; Barry, T.; Carriazo, C. Y.; Cole, A.; Gault, D.; Giles, B.; Giles, D.; Hill, K. M.; Howell, R. R.; Hudson, G.; Loader, B.; Mackie, J. A.; Olkin, C. B.; Rannou, P.; Regester, J.; Resnick, A.; Rodgers, T.; Sicardy, B.; Skrutskie, M. F.; Verbiscer, A. J.; Wasserman, L. H.; Watson, C. R.; Young, E. F.; Young, L. A.; Buie, M. W.; Nelson, M.

    2015-11-01

    The controversial question of aerosols in Pluto's atmosphere first arose in 1988, when features in a Pluto occultation lightcurve were alternately attributed to haze opacity (Elliot et al. 1989) or a thermal inversion (Eshleman 1989). A stellar occultation by Pluto in 2002 was observed from several telescopes on Mauna Kea in wavelengths ranging from R- to K-bands (Elliot et al. 2003). This event provided compelling evidence for haze on Pluto, since the mid-event baseline levels were systematically higher at longer wavelengths (as expected if there were an opacity source that scattered more effectively at shorter wavelengths). However, subsequent occultations in 2007 and 2011 showed no significant differences between visible and IR lightcurves (Young et al. 2011).The question of haze on Pluto was definitively answered by direct imaging of forward-scattering aerosols by the New Horizons spacecraft on 14-JUL-2015. We report on results of a bright stellar occultation which we observed on 29-JUN-2015 in B- and H-bands from both grazing and central sites. As in 2007 and 2011, we see no evidence for wavelength-dependent extinction. We will present an analysis of haze parameters (particle sizes, number density profiles, and fractal aggregations), constraining models of haze distribution to those consistent with and to those ruled out by the occultation lightcurves and the New Horizons imaging.References:Elliot, J.L., et al., "Pluto's Atmosphere." Icarus 77, 148-170 (1989)Eshleman, V.R., "Pluto's Atmosphere: Models based on refraction, inversion, and vapor pressure equilibrium." Icarus 80 439-443 (1989)Elliot, J.L., et al., "The recent expansion of Pluto's atmosphere." Nature 424 165-168 (2003)Young, E.F., et al., "Search for Pluto's aerosols: simultaneous IR and visible stellar occultation observations." EPSC-DPS Joint Meeting 2011, held 2-7 October 2011 in Nantes, France (2011)

  3. The Burst and Transient Source Experiment Earth Occultation Technique

    NASA Technical Reports Server (NTRS)

    Harmon, B. A.; Fishman, G. J.; Wilson, C. A.; Paciesas, W. S.; Zhang, S. N.; Finger, M. H.; Koshut, T. M.; McCollough, M. L.; Robinson, C. R.; Rubin, B. C.

    2002-01-01

    An Earth orbiting detector sensitive to gamma-ray photons will see step-like occultation features in its count rate when a gamma-ray point source crosses the Earth's limb. This is due to the change in atmospheric attenuation of the gamma rays along the line of sight. In an uncollimated detector, these occultation features can be used to locate and monitor astrophysical sources provided their signals can be individually separated from the detector background. We show that the Earth occultation technique applied to the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) is a viable and flexible all-sky monitor in the low-energy gamma-ray and hard X-ray energy range (20 keV-1 MeV). The method is an alternative to more sophisticated photon imaging devices for astronomy and can serve well as a cost-effective science capability for monitoring the high energy sky. Here we describe the Earth occultation technique for locating new sources and for measuring source intensity and spectra without the use of complex background models. Examples of transform imaging, step searches, spectra, and light curves are presented. Systematic uncertainties due to source confusion, detector response, and contamination from rapid background fluctuations are discussed and analyzed for their effect on intensity measurements. A sky location-dependent average systematic error is derived as a function of Galactic coordinates. The sensitivity of the technique is derived as a function of incident photon energy and also as a function of angle between the source and the normal to the detector entrance window. Occultations of the Crab Nebula by the Moon are used to calibrate Earth occultation flux measurements independent of possible atmospheric scattering effects.

  4. IGF-I and mammographic density in four geographic locations: a pooled analysis.

    PubMed

    Maskarinec, Gertraud; Takata, Yumie; Chen, Zhao; Gram, Inger Torhild; Nagata, Chisato; Pagano, Ian; Hayashi, Kentaro; Arendell, Leslie; Skeie, Guri; Rinaldi, Sabina; Kaaks, Rudolph

    2007-10-15

    Insulin-like growth factor (IGF-I) and prolactin have been found to be associated with breast cancer risk and with mammographic density. In a pooled analysis from 4 geographic locations, we investigated the association of percent mammographic density with serum levels of IGF-I, IGFBP-3 and prolactin. The pooled data set included 1,327 pre- and postmenopausal women: Caucasians from Norway, Arizona and Hawaii, Japanese from Hawaii and Japan, Latina from Arizona, and Native Hawaiians from Hawaii. Serum samples were assayed for IGF-I, IGFBP-3 and prolactin levels using ELISA assays. Mammographic density was quantified using a computer-assisted density method. After stratification by menopausal status, multiple regression models estimated the relation between serum analytes and breast density. All serum analytes except prolactin among postmenopausal women differed significantly by location/ethnicity group. Among premenopausal subjects, IGF-I levels and the molar ratio were highest in Hawaii, intermediate in Japan and lowest in Arizona. For IGFBP-3, the order was reversed. Among postmenopausal subjects, Norwegian women had the highest IGF-I levels and women in Arizona had the lowest while women in Japan and Hawaii had intermediate levels. We observed no significant relation between percent density and IGF-I or prolactin levels among pre-and postmenopausal women. The significant differences in IGF-I levels by location but not ethnicity suggest that environmental factors influence IGF-I levels, whereas percent breast density varies more according to ethnic background than by location. Based on this analysis, the influence of circulating levels of IGF-I, IGFBP-3, and prolactin on percent density appears to be very small.

  5. Associations of overall and abdominal adiposity with area and volumetric mammographic measures among postmenopausal women.

    PubMed

    Woolcott, Christy G; Cook, Linda S; Courneya, Kerry S; Boyd, Norman F; Yaffe, Martin J; Terry, Tim; Brant, Rollin; McTiernan, Anne; Bryant, Heather E; Magliocco, Anthony M; Friedenreich, Christine M

    2011-07-15

    Whereas mammographic density and adiposity are positively associated with postmenopausal breast cancer risk, they are inversely associated with one another. To examine the association between these two risk factors, a secondary analysis of data from a randomized controlled trial of a year-long aerobic exercise intervention was done. Participants were 302 postmenopausal women aged 50-74 years. Dense fibroglandular and nondense fatty tissue were measured from mammograms using computer-assisted thresholding software for area measurements and a technique relying on the calibration of mammography machines with a tissue-equivalent phantom for volumetric measurements. Adiposity was measured by anthropometry (body mass index, waist circumference), whole-body dual x-ray absorptiometry scans (body fat) and computed tomography scans (abdominal adiposity). Correlations were estimated between and within women, the latter representing the association between the 1-year change in adiposity and mammographic measures. Adiposity was correlated with nondense area and volume (0.50 ≤ r ≤ 0.66 between women; 0.18 ≤ r ≤ 0.46 within women). Between women, adiposity was correlated with dense area and volume (-0.12 ≤ r ≤ -0.30) and with percent dense area and volume (-0.28 ≤ r ≤ -0.48). Because measurements made with scans explained at most only 3% more of the variation in absolute or percent density beyond that explained by anthropometric measurements, anthropometric measurements are likely sufficient for adjustment of the association between mammographic density and breast cancer risk. Adiposity is associated with breast fatty tissue and possibly weakly inversely associated with fibroglandular tissue. PMID:20848591

  6. Varying performance in mammographic interpretation across two countries: Do results indicate reader or population variances?

    NASA Astrophysics Data System (ADS)

    Soh, BaoLin P.; Lee, Warwick B.; Wong, Jill; Sim, Llewellyn; Hillis, Stephen L.; Tapia, Kriscia A.; Brennan, Patrick C.

    2016-03-01

    Aim: To compare the performance of Australian and Singapore breast readers interpreting a single test-set that consisted of mammographic examinations collected from the Australian population. Background: In the teleradiology era, breast readers are interpreting mammographic examinations from different populations. The question arises whether two groups of readers with similar training backgrounds, demonstrate the same level of performance when presented with a population familiar only to one of the groups. Methods: Fifty-three Australian and 15 Singaporean breast radiologists participated in this study. All radiologists were trained in mammogram interpretation and had a median of 9 and 15 years of experience in reading mammograms respectively. Each reader interpreted the same BREAST test-set consisting of sixty de-identified mammographic examinations arising from an Australian population. Performance parameters including JAFROC, ROC, case sensitivity as well as specificity were compared between Australian and Singaporean readers using a Mann Whitney U test. Results: A significant difference (P=0.036) was demonstrated between the JAFROC scores of the Australian and Singaporean breast radiologists. No other significant differences were observed. Conclusion: JAFROC scores for Australian radiologists were higher than those obtained by the Singaporean counterparts. Whilst it is tempting to suggest this is down to reader expertise, this may be a simplistic explanation considering the very similar training and audit backgrounds of the two populations of radiologists. The influence of reading images that are different from those that radiologists normally encounter cannot be ruled out and requires further investigation, particularly in the light of increasing international outsourcing of radiologic reporting.

  7. Computer-aided detection of mammographic masses based on content-based image retrieval

    NASA Astrophysics Data System (ADS)

    Jin, Renchao; Meng, Bo; Song, Enmin; Xu, Xiangyang; Jiang, Luan

    2007-03-01

    A method for computer-aided detection (CAD) of mammographic masses is proposed and a prototype CAD system is presented. The method is based on content-based image retrieval (CBIR). A mammogram database containing 2000 mammographic regions is built in our prototype CBIR-CAD system. Every region of interested (ROI) in the database has known pathology. Specifically, there are 583 ROIs depicting biopsy-proven masses, and the rest 1417 ROIs are normal. Whenever a suspicious ROI is detected in a mammogram by a radiologist, it can be submitted as a query to this CBIRCAD system. As the query results, a series of similar ROI images together with their known pathology knowledge will be retrieved from the database and displayed in the screen in descending order of their similarities to the query ROI to help the radiologist to make the diagnosis decision. Furthermore, our CBIR-CAD system will output a decision index (DI) to quantitatively indicate the probability that the query ROI contains a mass. The DI is calculated by the query matches. In the querying process, 24 features are extracted from each ROI to form a 24-dimensional vector. Euclidean distance in the 24-dimensional feature vector space is applied to measure the similarities between ROIs. The prototype CBIR-CAD system is evaluated based on the leave-one-out sampling scheme. The experiment results showed that the system can achieve a receiver operating characteristic (ROC) area index A Z =0.84 for detection of mammographic masses, which is better than the best results achieved by the other known mass CAD systems.

  8. Occult laryngomalacia resulting in obstructive sleep apnea in an infant.

    PubMed

    Oomen, Karin P Q; Modi, Vikash K

    2013-09-01

    Classic laryngomalacia presents in the awake infant with progressive stridor when agitated. Occult laryngomalacia usually presents with stridor in children older than 2 years and is limited to sleep or exercise. There have been no documented cases of occult laryngomalacia causing obstructive sleep apnea in infants. We report the youngest documented case of an infant with state-dependent laryngomalacia resulting in severe obstructive sleep apnea. This patient was successfully treated with supraglottoplasty, with resolution of symptoms. In conclusion, state-dependent laryngomalacia resulting in obstructive sleep apnea may present in children younger than 12 months of age. In these individuals, supraglottoplasty should be considered. PMID:23911113

  9. Cassini First Diametric Radio Occultation of Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Marouf, E.; French, R.; Rappaport, N.; Kliore, A.; Flasar, M.; Nagy, A.; Ambrosini, R.; McGhee, C.; Schinder, P.; Anabtawi, A.; Barbinis, E.; Goltz, G.; Thomson, F.; Wong, K.

    2005-05-01

    We present preliminary results expected from the first planned Cassini radio occultation observation of Saturn's rings, to be conducted on May 3rd, 2005. The path of Cassini as seen from Earth (the occultation track) has been designed to cross the rings from the west to the east ansa almost diametrically, allowing for occultation of all major ring features at two widely separated longitudes (about 180 deg apart). The duration of the geometric occultation is about 1.5 hours on each side. During the occultation, Cassini transmits through the rings three coherent monochromatic radio signals of wavelength 0.94, 3.6, and 13 cm (Ka-, X-, and S-band respectively), a capability unique to Cassini. The perturbed signals received at the Earth are recorded at the NASA DSN complexes at Goldstone and Canberra. Both direct and forward-scattered components of the signal may be identified in spectrograms of the received signals. The time history of the extinction of the direct signal is expected to yield high-spatial-resolution optical depth and phase shift profiles of ring structure. The timing of the occultation was optimized to allow probing the rings when the ring-opening-angle B (the angle between the line-of-sight and the ring plane) is relatively large (B = 23 deg), hence maximizing chances of measuring for the first time the structure of the relatively optically thick Ring B. In a similar experiment by Voyager in 1980, excessive signal attenuation along the long path within the nearly closed rings (B = 5.9 deg) limited the utility of the observations in relatively thick ring regions, in particular the main Ring B. For the Cassini optimized occultation geometry, a large B, slow radial velocity along the occultation track, and much improved phase stability of the reference ultrastable oscillator (USO) on board Cassini combine to promise achievable radial resolution approaching 100 m over a good fraction of the rings. Measurement of the amplitude and phase of the diffracted

  10. Forthcoming Occultations of Astrometric Radio Sources by Planets

    NASA Technical Reports Server (NTRS)

    L'vov, Victor; Malkin, Zinovy; Tsekmeister, Svetlana

    2010-01-01

    Astrometric observations of radio source occultations by solar system bodies may be of large interest for testing gravity theories, dynamical astronomy, and planetary physics. In this paper, we present an updated list of the occultations of astrometric radio sources by planets expected in the coming years. Such events, like solar eclipses, generally speaking can only be observed in a limited region. A map of the shadow path is provided for the events that will occurr in regions with several VLBI stations and hence will be the most interesting for radio astronomy experiments.

  11. Astrometric analysis of Europa-Io occultations observed in 1991

    NASA Astrophysics Data System (ADS)

    Descamps, P.

    1994-11-01

    Astrometric results from an analysis of 36 lightcurves of Io's occultations by Europa, observed during 1991 in the visible bands, are presented. They are issued from the adjustment of a theoretical astrometric-photometric model to observations using Hapke's law. These observations are of importance because they give high quality astrometric information useful to the determination of the location of Io's hotspots. In fact, accurate positioning of hotspots on Io is made possible from infrared observations only if the occultation timing is well-known.

  12. Multiple imputation as a means to assess Mammographic vs. Ultrasound technology in Determine Breast Cancer Recurrence

    NASA Astrophysics Data System (ADS)

    Helenowski, Irene B.; Demirtas, Hakan; Khan, Seema; Eladoumikdachi, Firas; Shidfar, Ali

    2014-03-01

    Tumor size based on mammographic and ultrasound data are two methods used in predicting recurrence in breast cancer patients. Which technology offers better determination of diagnosis is an ongoing debate among radiologists, biophysicists, and other clinicians, however. Further complications in assessing the performance of each technology arise from missing data. One approach to remedy this problem may involve multiple imputation. Here, we therefore examine how imputation affects our assessment of the relationship between recurrence and tumor size determined either by mammography of ultrasound technology. We specifically employ the semi-parametric approach for imputing mixed continuous and binary data as presented in Helenowski and Demirtas (2013).

  13. Risk of Breast Cancer in Women with False-Positive Results according to Mammographic Features.

    PubMed

    Castells, Xavier; Torá-Rocamora, Isabel; Posso, Margarita; Román, Marta; Vernet-Tomas, Maria; Rodríguez-Arana, Ana; Domingo, Laia; Vidal, Carmen; Baré, Marisa; Ferrer, Joana; Quintana, María Jesús; Sánchez, Mar; Natal, Carmen; Espinàs, Josep A; Saladié, Francina; Sala, María

    2016-08-01

    Purpose To assess the risk of breast cancer in women with false-positive screening results according to radiologic classification of mammographic features. Materials and Methods Review board approval was obtained, with waiver of informed consent. This retrospective cohort study included 521 200 women aged 50-69 years who underwent screening as part of the Spanish Breast Cancer Screening Program between 1994 and 2010 and who were observed until December 2012. Cox proportional hazards regression analysis was used to estimate the age-adjusted hazard ratio (HR) of breast cancer and the 95% confidence interval (CI) in women with false-positive mammograms as compared with women with negative mammograms. Separate models were adjusted for screen-detected and interval cancers and for screen-film and digital mammography. Time without a breast cancer diagnosis was plotted by using Kaplan-Meier curves. Results When compared with women with negative mammograms, the age-adjusted HR of cancer in women with false-positive results was 1.84 (95% CI: 1.73, 1.95; P < .001). The risk was higher in women who had calcifications, whether they were (HR, 2.73; 95% CI: 2.28, 3.28; P < .001) or were not (HR, 2.24; 95% CI: 2.02, 2.48; P < .001) associated with masses. Women in whom mammographic features showed changes in subsequent false-positive results were those who had the highest risk (HR, 9.13; 95% CI: 8.28, 10.07; P < .001). Conclusion Women with false-positive results had an increased risk of breast cancer, particularly women who had calcifications at mammography. Women who had more than one examination with false-positive findings and in whom the mammographic features changed over time had a highly increased risk of breast cancer. Previous mammographic features might yield useful information for further risk-prediction models and personalized follow-up screening protocols. (©) RSNA, 2016 Online supplemental material is available for this article.

  14. Percent Mammographic Density and Dense Area as Risk Factors for Breast Cancer.

    PubMed

    Rauh, C; Hack, C C; Häberle, L; Hein, A; Engel, A; Schrauder, M G; Fasching, P A; Jud, S M; Ekici, A B; Loehberg, C R; Meier-Meitinger, M; Ozan, S; Schulz-Wendtland, R; Uder, M; Hartmann, A; Wachter, D L; Beckmann, M W; Heusinger, K

    2012-08-01

    Purpose: Mammographic characteristics are known to be correlated to breast cancer risk. Percent mammographic density (PMD), as assessed by computer-assisted methods, is an established risk factor for breast cancer. Along with this assessment the absolute dense area (DA) of the breast is reported as well. Aim of this study was to assess the predictive value of DA concerning breast cancer risk in addition to other risk factors and in addition to PMD. Methods: We conducted a case control study with hospital-based patients with a diagnosis of invasive breast cancer and healthy women as controls. A total of 561 patients and 376 controls with available mammographic density were included into this study. We describe the differences concerning the common risk factors BMI, parital status, use of hormone replacement therapy (HRT) and menopause between cases and controls and estimate the odds ratios for PMD and DA, adjusted for the mentioned risk factors. Furthermore we compare the prediction models with each other to find out whether the addition of DA improves the model. Results: Mammographic density and DA were highly correlated with each other. Both variables were as well correlated to the commonly known risk factors with an expected direction and strength, however PMD (ρ = -0.56) was stronger correlated to BMI than DA (ρ = -0.11). The group of women within the highest quartil of PMD had an OR of 2.12 (95 % CI: 1.25-3.62). This could not be seen for the fourth quartile concerning DA. However the assessment of breast cancer risk could be improved by including DA in a prediction model in addition to common risk factors and PMD. Conclusions: The inclusion of the parameter DA into a prediction model for breast cancer in addition to established risk factors and PMD could improve the breast cancer risk assessment. As DA is measured together with PMD in the process of computer-assisted assessment of PMD it might be considered to include it as one additional breast

  15. Theoretical performance of solar coronagraphs using sharp-edged or apodized circular external occulters

    NASA Astrophysics Data System (ADS)

    Aime, C.

    2013-10-01

    Context. This study focuses on an instrument able to monitor the corona close to the solar limb. Aims: We study the performance of externally occulted solar coronagraphs. We compute the shape of the umbra and penumbra produced by the occulter at the entrance aperture of the telescope and compare levels of rejection obtained for a circular occulter with a sharp or smooth transmission at the edge. Methods: We show that the umbral pattern in an externally occulted coronagraph can be written as a convolution product between the occulter diffraction pattern and an image of the Sun. We then focus on the analysis to circular symmetric occulters. We first derive an analytical expression using two Lommel series for the Fresnel diffraction pattern produced by a sharp-edged circular occulter. Two different expressions are used for inside and outside the occulter's geometric shadow. We verify that a numerical approach that directly solves the Huygens-Fresnel integral gives the same result. This suggests that the numerical computation can be used for a circular occulter with any variable transmission. Results: With the objective of observing the solar corona a few minutes from limb, a sharp-edged circular occulter of a few meters cannot produce an umbra darker than 10-4 of the direct sunlight. The same occulter, having an apodization zone of a few percent of the diameter (3 cm for a 1.5 m occulter), darkers the umbra down to 10-8 of the direct sunlight for linear transmission and to 10-12 for Sonine or cosine bell transmissions. An investigation for an apodized occulter with manufacturing defaults is quickly performed. Conclusions: It has been possible to numerically demonstrate the large superiority of apodized circular occulters with respect to the sharp-edged ones. These occulters allow the theoretical observation of the very limb-close corona with not yet obtained contrast ratios.

  16. Oh Glorious Geometry: Eclipses, Transits, and Occultations

    NASA Astrophysics Data System (ADS)

    Sinclair, R. M.

    2016-01-01

    Astronomical objects are like a grand clockwork in the sky; they follow steady patterns in time. However, these bright objects we see are not just points of light but have finite dimensions and thus can get in each other's way. As a result, some stars puzzle us by brightening or dimming, or the Sun can frighten us by going out unexpectedly when something else blocks its light. There is nothing unusual about these eclipses, occultations, or transits—they are demonstrations of simple physics—and we take some for granted, like the rotation of Earth moving us into darkness each night. The periodic dimming of a bright star worried mankind for millennia and helped give astronomy a shove. And unexpected events, like a solar or lunar eclipse, can inspire awe and change the course of history. Now that we can observe through telescopes and travel by proxy throughout the solar system, we find the universe is rife with shadow and light shows. Those taking place within our solar system have been useful to astronomy (like the recent transits of Venus or the ever-present eclipses of the Jovian satellites), and were of considerable popular interest, allowing us to think beyond the confines of Earth. Now we detect distant exoplanets transiting their parent stars, announcing the presence of other solar systems in our corner of the Galaxy and changing the discussion about life elsewhere in the universe from mere speculation to plausible possibility. Distant galaxies can make visible ever-further galaxies by forming Einstein rings, allowing us to see behind them and make the structure of the universe more evident. This paper will discuss these phenomena, from those visible easily on Earth to those that can now be seen for the first time from probes in space. We will also discuss how this has expanded popular knowledge of the universe we live in. This paper is illustrated by a number of examples ranging from eclipses and transits throughout the solar system and the nearby stars to

  17. Primary malignant melanoma

    PubMed Central

    Mısır, A. Ferhat; Durmuşlar, Mustafa C.; Zerener, Tamer; Gün, Banu D.

    2016-01-01

    Malignant melanomas (MM) of the oral cavity are extremely rare, accounting for 0.2% to 8.0% of all malignant melanomas. Malignant melanomas is more frequently seen at the level of the hard palate and gingiva. Early diagnosis and treatment are important for reducing morbidity. Malignant melanoma cells stain positively with antibodies to human melanoma black 45, S-100 protein, and vimentin; therefore, immunohistochemistry can play an important role in evaluating the depth of invasion and the location of metastases. A 76-year-old man developed an oral malignant melanoma, which was originally diagnosed as a bluish reactive denture hyperplasia caused by an ill-fitting lower denture. The tumor was removed surgically, and histopathological examination revealed a nodular-type MM. There was no evidence of recurrence over a 4-year follow-up period. PMID:27052289

  18. Occultations of stars by solar system objects. VIII - Occultations of catalog stars by asteroids, planets, Titan, and Triton in 1990 and 1991

    NASA Technical Reports Server (NTRS)

    Wasserman, L. H.; Bowell, E.; Millis, R. L.

    1990-01-01

    Predictions are given for occultations of catalog stars by asteroids, planets, Titan, and Triton in 1990 and 1991. The predictions are based on a computerized comparison of the occulting bodies' ephemerides and nine major star catalogs. The search is complete for all numbered asteroids whose angular diameters exceed 0.08 arcsec during the search years. Preliminary ground tracks are shown for the more favorable occultations.

  19. GPS Radio Occultation With Champ: The First Year of The Experiment

    NASA Astrophysics Data System (ADS)

    Wickert, J.; Beyerle, G.; Marquardt, C.; Schmidt, T.; Reigber, Ch.; König, R.; Grunwaldt, L.

    The GPS radio occultation experiment onboard the German CHAMP (CHAllenging Minisatellite Payload) satellite was started on February 11, 2001. During an one hour measurement period seven occultation events were recorded. Already these first mea- surements indicated that in spite of the activated anti-spoofing (A/S) mode of the GPS the state-of-the-art GPS flight receiver combined with favorable antenna characteris- tics allows for global atmosphere sounding with high accuracy and vertical resolution. More than 50,000 occultations are expected as of April 2002. The first year of the CHAMP occultation experiment is reviewed. The occultation infrastructure at the Ge- oForschungsZentrum (GFZ) Potsdam and the operational occultation data processing is characterized. An overview of GFZSs operational data processing, the scientific data analysis and the results of the first year occultation experiment is given. The quality of CHAMPSs occultation data products (vertical atmospheric profiles) is evaluated. Re- sults of data analysis using wave optic methods are presented, e.g. contributions from signals, reflected from EarthSs surface, were found in the occultation data in about 20-30% of the measurements using a radio holographic analysis. Furthermore, the termination of the Selective Availability (SA) mode of the GPS made the application of less-than-double-differencing techniques for GPS occultation analysis feasible. Re- sults of occultation data processing using a space-based single differencing technique are compared with those generated by double differencing as a reference.

  20. Drugs Approved for Malignant Mesothelioma

    MedlinePlus

    ... Professionals Questions to Ask about Your Treatment Research Drugs Approved for Malignant Mesothelioma This page lists cancer ... in malignant mesothelioma that are not listed here. Drugs Approved for Malignant Mesothelioma Alimta (Pemetrexed Disodium) Pemetrexed ...

  1. The Effect of Diurnal Variations on Ionospheric Radio Occultations

    NASA Astrophysics Data System (ADS)

    Yelle, Roger V.; Koskinen, Tommi; Withers, Paul; Schinder, Paul J.; Moses, Julianne I.; Mueller-Wodarg, Ingo

    2016-10-01

    Radio occultations are a powerful technique for the study of atmospheres and ionospheres by planetary spacecraft. For missions to the outer solar system, the occultations always probe the terminator region of the planet. The analysis of radio occultations typically assumes symmetry along the ray path in the horizontal direction about the tangent point. While this is an excellent assumption for the neutral atmosphere where the scale length of horizontal gradients is large, it is suspect for the ionosphere where electron densities decrease rapidly from day to night. Diurnal variations in peak electron density are often several orders of magnitude and may occur over a region of a few degrees. We investigate the consequences of diurnal variations on ionospheric occultations with a ray tracing calculation for the angular deflection and frequency residual of the radio wave. The calculations are based on photochemical/diffusion models for the ionospheres of Saturn and Titan. Differences from analysis based on the assumption of horizontal symmetry are most pronounced in the bottom side ionosphere where chemical time constants are short.

  2. Pluto-Charon stellar occultation candidates - 1990-1995

    NASA Technical Reports Server (NTRS)

    Dunham, E. W.; Mcdonald, S. W.; Elliot, J. L.

    1991-01-01

    A search to identify stars that might be occulted by Pluto or Charon during the period 1990-1995 and part of 1996 is studied. This search was made with an unfiltered CCD camera operated in the strip scanning mode, and it reaches an R magnitude of approximately 17.5 - about 1.5 mag fainter than previous searches. Circumstances for each of the 162 potential occultations are given, including an approximate R magnitude of the star, which allows estimation of the signal-to-noise ratio (S/N) for observation of each occultation. The faintest stars in the list would yield an S/N of about 20 for a 1 s integration when observed with a CCD detector on an 8 m telescope under a dark sky. The astrometric precision (+/- 0.2 arcsec, with larger systematic errors possible for individual cases) is insufficient to serve as a final prediction for these potential occultations, but is sufficient to identify stars deserving of further, more accurate, astrometric observations. Statistically, about 32 of these events to be observable somewhere on earth are expected. The number of events actually observed will be substantially smaller because of clouds and the sparse distribution of large telescopes. Finder charts for each of the 91 stars involved are presented.

  3. Pluto-Charon Stellar Occultation Candidates: 1990-1995

    NASA Technical Reports Server (NTRS)

    Dunham, E. W.; McDonald, S. W.; Elliot, J. L.

    1991-01-01

    We have carried out a search to identify stars that might be occulted by Pluto or Charon during the period 1990-1995 and part of 1996. This search was made with an unfiltered CCD camera operated in the strip scanning mode, and it reaches an R magnitude of approximately 17.5-about 1.5 mag fainter than previous searches. Circumstances for each of the 162 potential occultations are given, including an approximate R magnitude of the star, which allows estimation of the signal-to-noise ratio (S/N) for observation of each occultation. The faintest stars in our list would yield an S/N of about 20 for a 1 S integration when observed with a CCD detector on an 8 m telescope under a dark sky. Our astrometric precision (+/- 0.2 arcsec, with larger systematic errors possible for individual cases) is insufficient to serve as a final prediction for these potential occultations, but is sufficient to identify stars deserving of further, more accurate, astrometric observations. Statistically, we expect about 32 of these events to be observable somewhere on Earth. The number of events actually observed will be substantially smaller because of clouds and the sparse distribution of large telescopes. Finder charts for each of the 91 stars involved are presented.

  4. Phase retrieval applied to stellar occultation for asteroid silhouette characterization.

    PubMed

    Trahan, Russell; Hyland, David

    2014-06-01

    Here we expand on the current methods of characterizing small astronomical bodies, particularly asteroids, by viewing stellar occultation events. Stellar occultation has proven to be a viable method for determining the size of moons and asteroids; however, it comes with some limitations. In general the method does not consider or use all of the known diffraction effects that occur and thus provides a nominal radius--not a shape--of the occluder. We show that most stellar occultation events involving small near-Earth asteroids occur with low Fresnel numbers. This in effect renders the traditional methods useless to characterize the shape, because no sharp shadow exists. We show that using similar data collection to that of the traditional occultation method and inverting a Fresnel diffraction equation by a phase retrieval process can yield a complete reconstruction of the silhouette of the occluder. The effect of noise in the measurements is also discussed. A practical example applied to the asteroid 25143 Itokawa is shown. PMID:24922432

  5. An upcoming occultation of a star by Uranus.

    NASA Astrophysics Data System (ADS)

    Melillo, F. J.

    1998-07-01

    Observers in the British Isles, southwestern Europe, Africa, South and Central America and the eastern United States and Canada should mark their calendars for 1998 Aug 27 UT, when there will occur a rare occultation of a +9.5-magnitude star (PPM 237981 in Capricornus) by Uranus.

  6. Infrared diameter of IRC + 10216 determined from lunar occultations.

    NASA Technical Reports Server (NTRS)

    Toombs, R. I.; Becklin, E. E.; Westphal, J. A.; Frogel, J. A.; Law, S. K.; Porter, F. C.

    1972-01-01

    Lunar occultations of IRC + 10216 have been used to determine the size of the regions emitting 2.2-, 3.5-, 4.8-, and 10-micron radiation. The results are interpreted as the first direct measurement of the physical size of a dust shell surrounding a late-type star.

  7. Occult hemoglobin as an indicator of impingement stress in fishes

    SciTech Connect

    Not Available

    1980-01-01

    During the process of impingement on cooling system intake screens, fish may be subject to different types of stress, the total of which often results in the death of individual fish. This report assesses the use of occult hemoglobin in fish demand mucus as an indicator of impingement stress. (ACR)

  8. Counseling the Occult-Involved Student: Guidelines and Suggestions.

    ERIC Educational Resources Information Center

    Carmichael, Karla D.

    1993-01-01

    Contends that counselors working with public school students needs to be aware of the four main levels of involvement in the occult (fun-and-games, dabblers, serious involvement, and criminal involvement). Each of the four levels is described, warning signs are identified, and the counselor's role is explained as one of support and prevention. (NB)

  9. Stellar Occultation Studies of Pluto, Triton, Charon, and Chiron

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    2002-01-01

    Bodies inhabiting the outer solar system are of interest because, due to the colder conditions, they exhibit unique physical processes. Also, some of the lessons learned from them can be applied to understanding what occurred in the outer solar system during its formation and early evolution. The thin atmospheres of Pluto and Triton have structure that is not yet understood, and they have been predicted to undergo cataclysmic seasonal changes. Charon may have an atmosphere - we don't know. Chiron exhibits cometary activity so far from the sun (much further than most comets), so that H2O sublimation cannot be the driving mechanism. Probing these bodies from Earth with a spatial resolution of a few kilometers can be accomplished only with the stellar occultation technique. In this program we find and predict stellar occultation events by small outer-solar system bodies and then attempt observations of the ones that can potentially answer interesting questions. We also develop new methods of data analysis for occultations and secure other observations that are necessary for interpretation of the occultation data.

  10. Occult hepatitis B virus infection in hemodialysis patients in Japan.

    PubMed

    Saijo, Tomokatsu; Joki, Nobuhiko; Inishi, Yoji; Muto, Mikako; Saijo, Motohiko; Hase, Hiroki

    2015-04-01

    Hepatitis B surface antigen is widely used in hepatitis B virus surveillance; patients who test negative for the antigen are judged to be uninfected. However, occult hepatitis B virus infection has been confirmed with hepatitis B virus DNA at low levels in the liver and peripheral blood in patients positive for hepatitis B core antibody or hepatitis B surface antibody, even if they test negative for hepatitis B surface antigen. To investigate the prevalence of occult hepatitis B virus in hemodialysis patients, we performed cross-sectional analysis of 161 hemodialysis patients in two related institutions for hepatitis B surface antigen, hepatitis B core antibody, and hepatitis B surface antibody. Hepatitis B surface antigen, hepatitis B core antibody, or hepatitis B surface antibody was present in 45 patients (28.0%). Hepatitis B virus DNA was present in six patients (3.7%), all of whom also tested positive for hepatitis B core antibody. Hepatitis B surface antibody positivity was unrelated in only one of the six patients. Four of the six patients were positive for hepatitis B surface antigen; however, two (1.3%) of these with occult hepatitis B virus infection were found to be hepatitis B surface antigen negative. Occult hepatitis B virus infection may be missed in hepatitis B virus surveillance using hepatitis B surface antigen alone; therefore, routine hepatitis B core antibody screening is necessary. Patients who test positive for hepatitis B core antibody should undergo further hepatitis B virus DNA testing to enable accurate hepatitis B virus screening.

  11. Early Observations in the Taiwanese-American Occultation Survey

    NASA Astrophysics Data System (ADS)

    Alcock, C.; Bianco, F.; Lehner, M.; Dave, R.; Giammarco, J.; Schwamb, M.; Cook, K.; Marshall, S.; de Pater, I.; Porrata, R.; Rice, J.; Lissauer, J.; Lee, T.; King, S. K.; Wang, A.; Wang, S. Y.; Wen, C. Y.; Chen, W. P.; Ip, W.; Chang, Y. H.; Kinoshita, D.; Lin, H. C.; Mondal, S.; Zhang, Z. W.; Axelrod, T.; Byun, Y. I.

    2005-12-01

    The Taiwanese-American Occultation Survey (TAOS) is a program dedicated to performing a survey of the size and number distribution for small bodies (< 10km) in the Kuiper Belt. These objects are too faint to be detected through traditional means, but can be observed via their occultations of background stars. This technique is challenging due to the low event rate, the short event duration (< 200ms), marginal signal to noise of detections, and the possibility of a high false detection rate due to atmospheric fluctuations or other terrestrial phenomena. TAOS overcomes these obstacles with a four robotic telescope array (50cm) located in Lulin, Taiwan. Each telescope is equipped with a 2048 x 2048 pixel CCD camera. All four telescopes synchronously monitor up to 2000 stars autonomously at 5 Hz. We discuss the current state of the survey and the overall performance of the system during predicted asteroid occultations. In particular, we discuss our two telescope response to the occultation by (1723) Klemola of HIP 050535 (V = 8.46), with a maximal duration of 1.3 seconds and 7.2 magnitude drop.

  12. Capabilities and Limitations of Radio Occultation Measurements for Ionosphere Monitoring

    NASA Technical Reports Server (NTRS)

    Hajj, G. A.; Romans, L. J.; Pi, X.; Wang, Chunming

    1999-01-01

    The paper: (1) describes the range of capabilities of GPS radio occultation missions in ionospheric research: (a) ionospheric profiling; (b) ionospheric imaging; (c) ionospheric data assimilation; and (d) measurement of scintillation. (2) Identify strengths and weaknesses of measurements: (a) coverage; (b) resolution; and (c) uniqueness of solution.

  13. A novel approach to computer-aided diagnosis of mammographic images

    SciTech Connect

    Sari-Sarraf, H.; Gleason, S.S.; Hudson, K.T.; Hubner, K.F.

    1996-08-01

    This is a work-in-progress report of a research endeavor that deals with the design and development of a novel approach to computer-aided diagnosis (CAD) of mammographic images. With the initial emphasis being on the analysis of microcalcifications, the proposed approach defines a synergistic paradigm that utilizes new methodologies together with previously developed techniques. The new paradigm is intended to promote a higher degree of accuracy in CAD of mammograms with an increased overall throughput. The process of accomplishing these goals is initiated by the fractal encoding of the input image, which gives rise to the generation of focus-of-attention regions (FARs), that is, regions that contain anomalies. The primary thrust of this work is to demonstrate that by considering FARs, rather than the entire input image, the performances of the ensuing processes (i.e., segmentation, feature extraction, and classification) are enhanced in terms of accuracy and speed. After presenting the proposed approach to CAD of mammographic images, the paper describes the generation of FARs. Furthermore, an experimental study is included that demonstrates the impact of this front-end procedure on the process of microcalcification segmentation. Specifically, the experimentation reveals a dramatic decrease (increase) in the amount of input data (throughput), as well as a reduction in the number of false detections.

  14. Automated assessment of bilateral breast volume asymmetry as a breast cancer biomarker during mammographic screening

    NASA Astrophysics Data System (ADS)

    Williams, Alex C.; Hitt, Austin; Voisin, Sophie; Tourassi, Georgia

    2013-03-01

    The biological concept of bilateral symmetry as a marker of developmental stability and good health is well established. Although most individuals deviate slightly from perfect symmetry, humans are essentially considered bilaterally symmetrical. Consequently, increased fluctuating asymmetry of paired structures could be an indicator of disease. There are several published studies linking bilateral breast size asymmetry with increased breast cancer risk. These studies were based on radiologists' manual measurements of breast size from mammographic images. We aim to develop a computerized technique to assess fluctuating breast volume asymmetry in screening mammograms and investigate whether it correlates with the presence of breast cancer. Using a large database of screening mammograms with known ground truth we applied automated breast region segmentation and automated breast size measurements in CC and MLO views using three well established methods. All three methods confirmed that indeed patients with breast cancer have statistically significantly higher fluctuating asymmetry of their breast volumes. However, statistically significant difference between patients with cancer and benign lesions was observed only for the MLO views. The study suggests that automated assessment of global bilateral asymmetry could serve as a breast cancer risk biomarker for women undergoing mammographic screening. Such biomarker could be used to alert radiologists or computer-assisted detection (CAD) systems to exercise increased vigilance if higher than normal cancer risk is suspected.

  15. Correlates of mammographic density in B-mode ultrasound and real time elastography.

    PubMed

    Jud, Sebastian Michael; Häberle, Lothar; Fasching, Peter A; Heusinger, Katharina; Hack, Carolin; Faschingbauer, Florian; Uder, Michael; Wittenberg, Thomas; Wagner, Florian; Meier-Meitinger, Martina; Schulz-Wendtland, Rüdiger; Beckmann, Matthias W; Adamietz, Boris R

    2012-07-01

    The aim of our study involved the assessment of B-mode imaging and elastography with regard to their ability to predict mammographic density (MD) without X-rays. Women, who underwent routine mammography, were prospectively examined with additional B-mode ultrasound and elastography. MD was assessed quantitatively with a computer-assisted method (Madena). The B-mode and elastography images were assessed by histograms with equally sized gray-level intervals. Regression models were built and cross validated to examine the ability to predict MD. The results of this study showed that B-mode imaging and elastography were able to predict MD. B-mode seemed to give a more accurate prediction. R for B-mode image and elastography were 0.67 and 0.44, respectively. Areas in the B-mode images that correlated with mammographic dense areas were either dark gray or of intermediate gray levels. Concerning elastography only the gray levels that represent extremely stiff tissue correlated positively with MD. In conclusion, ultrasound seems to be able to predict MD. Easy and cheap utilization of regular breast ultrasound machines encourages the use of ultrasound in larger case-control studies to validate this method as a breast cancer risk predictor. Furthermore, the application of ultrasound for breast tissue characterization could enable comprehensive research concerning breast cancer risk and breast density in young and pregnant women.

  16. Correlates of mammographic density in B-mode ultrasound and real time elastography.

    PubMed

    Jud, Sebastian Michael; Häberle, Lothar; Fasching, Peter A; Heusinger, Katharina; Hack, Carolin; Faschingbauer, Florian; Uder, Michael; Wittenberg, Thomas; Wagner, Florian; Meier-Meitinger, Martina; Schulz-Wendtland, Rüdiger; Beckmann, Matthias W; Adamietz, Boris R

    2012-07-01

    The aim of our study involved the assessment of B-mode imaging and elastography with regard to their ability to predict mammographic density (MD) without X-rays. Women, who underwent routine mammography, were prospectively examined with additional B-mode ultrasound and elastography. MD was assessed quantitatively with a computer-assisted method (Madena). The B-mode and elastography images were assessed by histograms with equally sized gray-level intervals. Regression models were built and cross validated to examine the ability to predict MD. The results of this study showed that B-mode imaging and elastography were able to predict MD. B-mode seemed to give a more accurate prediction. R for B-mode image and elastography were 0.67 and 0.44, respectively. Areas in the B-mode images that correlated with mammographic dense areas were either dark gray or of intermediate gray levels. Concerning elastography only the gray levels that represent extremely stiff tissue correlated positively with MD. In conclusion, ultrasound seems to be able to predict MD. Easy and cheap utilization of regular breast ultrasound machines encourages the use of ultrasound in larger case-control studies to validate this method as a breast cancer risk predictor. Furthermore, the application of ultrasound for breast tissue characterization could enable comprehensive research concerning breast cancer risk and breast density in young and pregnant women. PMID:22123663

  17. Mammographic density measured as changes in tissue structure caused by HRT

    NASA Astrophysics Data System (ADS)

    Raundahl, Jakob; Loog, Marco; Nielsen, Mads

    2006-03-01

    Numerous studies have investigated the relation between mammographic density and breast cancer risk. These studies indicate that women with high breast density have a four to six fold risk increase. An investigation of whether or not this relation is causal is important for, e.g., hormone replacement therapy (HRT), which has been shown to actually increase the density. No gold standard for automatic assessment of mammographic density exists. Manual methods such as Wolfe patterns and BI-RADS are helpful for communication of diagnostic sensitivity, but they are both time consuming and crude. They may be sufficient in certain cases and for single measurements, but for serial, temporal analysis it is necessary to be able to detect more subtle changes and, in addition, to be more reproducible. In this work an automated method for measuring the effect of HRT w.r.t. changes in biological density in the breast is presented. This measure is a novel measure, which provides structural information orthogonal to intensity-based methods. Hessian eigenvalues at different scales are used as features and a clustering of these is employed to divide a mammogram into four structurally different areas. Subsequently, based on the relative size of the areas, a density score is determined. In the experiments, two sets of mammograms of 50 patients from a double blind, placebo controlled HRT experiment were used. The change in density for the HRT group, measured with the new method, was significantly higher (p = 0.0002) than the change in the control group.

  18. Bismuth Sulfide Nanoflowers for Detection of X-rays in the Mammographic Energy Range

    PubMed Central

    Nambiar, Shruti; Osei, Ernest K.; Yeow, John T. W.

    2015-01-01

    The increased use of diagnostic x-rays, especially in the field of medical radiology, has necessitated a significant demand for high resolution, real-time radiation detectors. In this regard, the photoresponse of bismuth sulfide (Bi2S3), an n-type semiconducting metal chalcogenide, to low energy x-rays has been investigated in this study. In recent years, several types of nanomaterials of Bi2S3 have been widely studied for optoelectronic and thermoelectric applications. However, photoresponse of Bi2S3 nanomaterials for dosimetric applications has not yet been reported. The photosensitivity of Bi2S3 with nanoscale “flower-like” structures was characterized under x-ray tube-potentials typically used in mammographic procedures. Both dark current and photocurrent were measured under varying x-ray doses, field sizes, and bias voltages for each of the tube potentials – 20, 23, 26 and 30 kV. Results show that the Bi2S3 nanoflowers instantaneously responded to even minor changes in the dose delivered. The photoresponse was found to be relatively high (few nA) at bias voltage as low as +1 V, and fairly repeatable for both short and long exposures to mammographic x-rays with minimal or no loss in sensitivity. The overall dose-sensitivity of the Bi2S3 nanoflowers was found to be similar to that of a micro-ionization chamber. PMID:25801531

  19. Bismuth sulfide nanoflowers for detection of X-rays in the mammographic energy range.

    PubMed

    Nambiar, Shruti; Osei, Ernest K; Yeow, John T W

    2015-03-24

    The increased use of diagnostic x-rays, especially in the field of medical radiology, has necessitated a significant demand for high resolution, real-time radiation detectors. In this regard, the photoresponse of bismuth sulfide (Bi2S3), an n-type semiconducting metal chalcogenide, to low energy x-rays has been investigated in this study. In recent years, several types of nanomaterials of Bi2S3 have been widely studied for optoelectronic and thermoelectric applications. However, photoresponse of Bi2S3 nanomaterials for dosimetric applications has not yet been reported. The photosensitivity of Bi2S3 with nanoscale "flower-like" structures was characterized under x-ray tube-potentials typically used in mammographic procedures. Both dark current and photocurrent were measured under varying x-ray doses, field sizes, and bias voltages for each of the tube potentials - 20, 23, 26 and 30 kV. Results show that the Bi2S3 nanoflowers instantaneously responded to even minor changes in the dose delivered. The photoresponse was found to be relatively high (few nA) at bias voltage as low as +1 V, and fairly repeatable for both short and long exposures to mammographic x-rays with minimal or no loss in sensitivity. The overall dose-sensitivity of the Bi2S3 nanoflowers was found to be similar to that of a micro-ionization chamber.

  20. Human performance for detection and discrimination of simulated microcalcifications in mammographic backgrounds

    NASA Astrophysics Data System (ADS)

    Reiser, Ingrid; Nishikawa, Robert M.

    2005-04-01

    We conducted experiments to determine human performance in detecting and discriminating microcalcification-like objects in mammographic background. This study is an extension of our previous work where we investigated detection and discrimination of known objects in white noise background (SKE/BKE taks). In the present experiments, we used hybrid images, consisting of computer-generated images of three signal shapes which were added into mammographic background extracted from digitized normal mammograms. Human performance was measured by determining percentage correct (PC) in 2-AFC experiments for the tasks of detecting a signal or discriminating between two signal shapes. PC was converted into a detection or discrimination index d' and psychometric functions were created by plotting d' as function of square root of signal energy. Human performance was compared to predictions of a NPWE model observer. We found that the slope of the linear portion of the psychometric function for detection was smaller than that for discrimination, as opposed to what we we observed for white noise backgrounds, where the psychometric function for detection was significantly steeper than that for discrimination. We found that human performance was qualitatively reproduced by model observer predictions.

  1. Mammography workstation design: effect on mammographer behaviour and the risk of musculoskeletal disorders

    NASA Astrophysics Data System (ADS)

    Taylor-Phillips, S.; Wallis, M. G.; Gale, A. G.

    2008-03-01

    In the UK Breast Screening Programme there is a growing transition from film to digital mammography, and consequently a change in mammography workstation ergonomics. This paper investigates the effect of the change for radiologists including their comfort, likelihood of developing musculoskeletal disorders (MSD's), and work practices. Three workstations types were investigated: one with all film mammograms; one with digital mammograms alongside film mammograms from the previous screening round, and one with digital mammograms alongside digitised film mammograms from the previous screening round. Mammographers were video-taped whilst conducting work sessions at each of the workstations. Event based Rapid Upper Limb Assessment (RULA) postural analysis showed no overall increase in MSD risk level in the switch from the film to digital workstation. Average number of visual glances at the prior mammograms per case measured by analysis of recorded video footage showed an increase if the prior mammograms were digitised, rather than displayed on a multi-viewer (p<.05). This finding has potential implications for mammographer performance in the transition to digital mammography in the UK.

  2. Mammographic density and the risk of breast cancer in Japanese women

    PubMed Central

    Nagata, C; Matsubara, T; Fujita, H; Nagao, Y; Shibuya, C; Kashiki, Y; Shimizu, H

    2005-01-01

    Using an automated method for detecting mammographic mass, the authors evaluated the relation between quantitatively measured density and the risk of breast cancer in a case–control study among Japanese women. The case subjects were 146 women newly diagnosed and histologically confirmed with breast cancer at a general hospital. A total of 659 control women were selected from those who attended a breast cancer mass screening at this hospital. Significantly increased odds ratios (ORs) of breast cancer were observed for breast densities of 25–49 and 50–74%, but not for densities of 75–100% as compared with 0% in premenopausal women after controlling for covariates (ORs=4.0, 4.3, and 1.4, respectively). In postmenopausal women, ORs were significantly increased for breast densities of 25–50% (OR=3.0) and 50–100% (OR=4.2). Total breast area was significantly associated with the risk of breast cancer independent of density percent or dense area in postmenopausal women. These data suggested that mammographic density was associated with the risk of breast cancer in Japanese women as is the case in Caucasian women. However, the associations of the risk of breast cancer with breast size and a high breast density greater than 75%, needs to be confirmed in future studies. PMID:15956963

  3. Computer-aided evaluation of radiologist's reproducibility and subjectivity in mammographic density assessment.

    PubMed

    Tomas, Ilijan; Kotoromanović, Zdenka; Belaj, Nenad; Margaretić, Damir; Ivezić, Zdravko; Katić, Miroslav; Zibar, Lada; Faj, Dario; Stimac, Damir; Matić, Mate

    2013-12-01

    Mammographic density is an independent risk of breast cancer. This study has evaluated the radiologists' reproducibility and subjectivity in breast density estimation and in order to decrease the radiologists' subjective errors the computer software was developed. The very good reproducibility existed in the strong correlation with the first and the second mammogram assessment after three month period for each radiologist (correlation coefficient 0.73-1, p < 0.001). The strong correlation was present in the case of all 5 radiologists when compared among themselves and compared with software aided MDEST-Mammographic Density Estimation (correlation coefficient 0.651-0.777, p < 0.001). Detected differences in glandular tissue percentage determination occurred in the case of two experienced radiologists, out of 5 (one radiologist with more than 5 year experience and one with more than 10 year experience, p < 0.01), but in the case of breast type determination (American College of Radiology-ACR I-IV), the detected difference occurred in one radiologist with the least experience (less than 5 years, p < 0.001). It can be concluded that the estimation of glandular tissue percentage in breast density is rather subjective method, especially if it is expressed with absolute percentage, but the determination of type of breast (ARCI-IV) depends on the radiologist's experience. This study showed that software aided determination of glandular tissue percentage and breast type can be of a great benefit in the case of less experienced radiologists.

  4. Brief Communication: Reproductive and lifestyle risk factors and mammographic density in Mexican women

    PubMed Central

    Rice, Megan S.; Bertrand, Kimberly A.; Lajous, Martin; Tamimi, Rulla M.; Torres, Gabriela; López-Ridaura, Ruy; Romieu, Isabelle

    2016-01-01

    Purpose Several breast cancer risk factors have been consistently associated with mammographic density (MD); however, data are limited for Hispanic women. Methods We examined data from 1007 premenopausal and 600 postmenopausal women in the Mexican Teachers’ Cohort (MTC). Multivariable linear regression was used to estimate associations between risk factors and MD. Results Among premenopausal women, age, current body mass index (BMI), BMI at age 18, and weight change since age 18 were inversely associated with percent MD, whereas benign breast disease (BBD), alcohol intake, and breastfeeding ≥12 months were associated with higher percent MD. Among postmenopausal women, age, current BMI, BMI at age 18, weight change since age 18, and speaking/having parents who speak an indigenous language were inversely associated with percent MD, while BBD and greater age at natural menopause, were positively associated with percent MD. Other breast cancer risk factors, such as age at menarche, parity, and age at first pregnancy, were not significantly associated with density in either premenopausal or postmenopausal women. Conclusion Results from the MTC are generally consistent with predictors of mammographic density observed in primarily non-Hispanic white populations; however, certain risk factors (e.g., parity) were not significantly associated with MD. PMID:26475982

  5. Automated assessment of bilateral breast volume asymmetry as a breast cancer biomarker during mammographic screening

    SciTech Connect

    Williams, Alex C; Hitt, Austin N; Voisin, Sophie; Tourassi, Georgia

    2013-01-01

    The biological concept of bilateral symmetry as a marker of developmental stability and good health is well established. Although most individuals deviate slightly from perfect symmetry, humans are essentially considered bilaterally symmetrical. Consequently, increased fluctuating asymmetry of paired structures could be an indicator of disease. There are several published studies linking bilateral breast size asymmetry with increased breast cancer risk. These studies were based on radiologists manual measurements of breast size from mammographic images. We aim to develop a computerized technique to assess fluctuating breast volume asymmetry in screening mammograms and investigate whether it correlates with the presence of breast cancer. Using a large database of screening mammograms with known ground truth we applied automated breast region segmentation and automated breast size measurements in CC and MLO views using three well established methods. All three methods confirmed that indeed patients with breast cancer have statistically significantly higher fluctuating asymmetry of their breast volumes. However, statistically significant difference between patients with cancer and benign lesions was observed only for the MLO views. The study suggests that automated assessment of global bilateral asymmetry could serve as a breast cancer risk biomarker for women undergoing mammographic screening. Such biomarker could be used to alert radiologists or computer-assisted detection (CAD) systems to exercise increased vigilance if higher than normal cancer risk is suspected.

  6. Sensing Water Vapon via Spacecraft Radio Occultation Observations

    NASA Technical Reports Server (NTRS)

    Kursinski, E. Robert; Hajj, George A.

    2000-01-01

    The radio occultation technique has been used to characterize planetary atmospheres since the 1960's spanning atmospheric pressures from 16 microbars to several bars. In 1988, the use of GPS signals to make occultation observations of Earth's atmosphere was realized by Tom Yunck and Gunnar Lindal at JPL. In the GPS to low-Earth-orbiter limb- viewing occultation geometry, Fresnel diffraction yield a unique combination of high vertical resolution of 100 m to 1 km at long wavelengths (approx. 20 cm) insensitive to particulate scattering which allows routine limb sounding from the lower mesosphere through the troposphere. A single orbiting GPS/GLONASS receiver can observe - 1000 to 1400 daily occultations providing as many daily, high vertical resolution soundings as the present global radiosonde network, but with far more evenly distributed, global coverage. The occultations yield profiles of refractivity as a function of height. In the cold, dry conditions of the upper troposphere and above (T less than 240 K), profiles of density, pressure (geopotential), and temperature can be derived. Given additional temperature information, water vapor can be derived in the midddle and lower troposphere with a unique combination of vertical resolution, global distribution and insensitivity to clouds and precipitation to an accuracy of approx. 0.2 g/kg. At low latitudes, moisture profiles will be accurate to 1-5% within the convective boundary layer and better than 20% below 6 to 7 km. Accuracies of climatological averages should be approx. 0. 1 g/kg limited by the biases in the temperature estimates. To use refractivity to constrain water vapor, knowledge of temperature is required. The simplest approach is to use the temperature field from an analysis such as the 6 hour ECMWF global analysis interpolated to the locations of each occultation. A better approach is to combine the temperature and moisture fields from such an analysis with the occultation refractivity in a weighting

  7. Effects of menopausal hormonal therapy on occult breast tumors.

    PubMed

    Santen, Richard J; Song, Yan; Yue, Wei; Wang, Ji-Ping; Heitjan, Daniel F

    2013-09-01

    An estimated 7% of 40-80 year old women dying of unrelated causes harbor occult breast tumors at autopsy. These lesions are too small to be detected by mammography, a method which requires tumors to be approximately 1cm in diameter to be diagnosed. Tumor growth rates, as assessed by "effective doubling times" on serial mammography range from 10 to >700 days with a median of approximately 200 days. We previously reported two models, based on iterative analysis of these parameters, to describe the biologic behavior of undiagnosed, occult breast tumors. One of our models is biologically based and includes parameters of a 200 day effective doubling time, 7% prevalence of occult tumors in the 40-80 aged female population and a detection threshold of 1.16 cm and the other involves computer based projections based on age related breast cancer incidence. Our models facilitate interpretation of the Women's Health Initiative (WHI) and anti-estrogen prevention studies. The biologically based model suggests that menopausal hormone therapy with conjugated equine estrogens plus medroxyprogesterone acetate (MPA) in the WHI trial primarily promoted the growth of pre-existing, occult lesions and minimally initiated de novo tumors. The paradoxical reduction of breast cancer incidence in women receiving estrogen alone is consistent with a model that this hormone causes apoptosis in women deprived of estrogen long term as a result of the cessation of estrogen production after the menopause. Understanding of the kinetics of occult tumors suggests that breast cancer "prevention" with anti-estrogens or aromatase inhibitors represents early treatment rather than a reduction in de novo tumor formation. Our in vivo data suggest that the combination of a SERM, bazedoxifene (BZA), with conjugated equine estrogen (CEE) acts to block maturation of the mammary gland in oophorectomized, immature mice. This hormonal combination is defined by the generic term, tissue selective estrogen complex or

  8. Classification of F ring features observed in Cassini UVIS occultations

    NASA Astrophysics Data System (ADS)

    Meinke, Bonnie K.; Esposito, Larry W.; Albers, Nicole; Sremčević, Miodrag

    2012-03-01

    The Cassini Ultraviolet Imaging Spectrograph (UVIS) has detected 27 statistically significant features in 101 occultations by Saturn’s F ring since July 2004. This work nearly doubles the number of features reported by Esposito et al. (Esposito, L.W. et al. [2008]. Icarus 194, 278-289). As the number of statistically significant features has grown, it has become useful to classify them for the purposes of cataloging. We define three classes: Moonlet, Icicle, and Core, which visually classify the shapes of features seen to date in the occultation profiles of Saturn’s F ring. Two features fall into the Moonlet class. Each is opaque in its occultation, which makes them candidates for solid objects. A majority of features are classified as Icicles, which partially block stellar signal for 22 m to just over 3.7 km along the radial expanse of the occultation. The density enhancements responsible for such signal attenuations are likely due to transient clumping of material, evidence that aggregations of material are ubiquitous in the F ring. Finally, the variety of core region shapes displays how even the general shape of the F ring is ever-changing. The core region of the F ring (typically ∼10 km wide) usually has a smooth U-shape to it, but the core region takes the shape of Ws and Vs in some occultation profiles. Our lengthy observing campaign reveals that Icicles are likely transient clumps, moonlets are possible solid objects, and cores show the variety of F ring morphology. We suggest that icicles may evolve into moonlets, which are an order of magnitude less abundant.

  9. OCCULTATION OBSERVATIONS OF SATURN'S B RING AND CASSINI DIVISION

    SciTech Connect

    French, Richard G.; McGhee, Colleen A.; Marouf, Essam A.; Rappaport, Nicole J.

    2010-04-15

    The outer edge of Saturn's B ring is strongly affected by the nearby 2:1 inner Lindblad resonance of Mimas and is distorted approximately into a centered elliptical shape, which at the time of the Voyager 1 and 2 encounters was oriented with its periapse toward Mimas. Subsequent observations have shown that the actual situation is considerably more complex. We present a complete set of historical occultation measurements of the B-ring edge, including the 1980 Voyager 1 and 1981 Voyager 2 radio and stellar occultations, the 1989 occultation of 28 Sgr, two independently analyzed occultations observed with the Hubble Space Telescope in 1991 and 1995, and a series of ring profiles from 12 diametric (ansa-to-ansa) occultations observed in 2005, using the Cassini Radio Science Subsystem (RSS). After making an approximate correction for systematic errors in the reconstructed spacecraft trajectories, we obtain orbit fits to features in the rings with rms residuals well under 1 km, in most cases. Fits to the B-ring edge in the RSS data reveal a systematic variation in the maximum optical depth at the very edge of the ring as a function of its orbital radius. We compare the B-ring measurements to an m = 2 distortion aligned with Mimas, and show that there have been substantial phase shifts over the past 25 years. Finally, we present freely precessing equatorial elliptical models for 16 features in the Cassini Division. The inner edges of the gaps are generally eccentric, whereas the outer edges are nearly circular, with ae < 0.5 km.

  10. Changes in mammographic density over time in breast cancer cases and women at high risk for breast cancer.

    PubMed

    Work, Meghan E; Reimers, Laura L; Quante, Anne S; Crew, Katherine D; Whiffen, Amy; Terry, Mary Beth

    2014-10-01

    High mammographic breast density is one of the strongest intermediate markers of breast cancer risk, and decreases in density over time have been associated with decreases in breast cancer risk. Using repeated measures of mammographic density in a cohort of high-risk women, the Women at Risk (WAR) cohort at Columbia University Medical Center (N = 2670), we examined whether changes in prediagnostic mammographic density differed among 85 prospectively-ascertained breast cancer cases and 85 age-matched controls, using a nested case-control design. Median age at first mammogram was 51 years (range, 29-77 years), with a median of 4 years between first and second prediagnostic mammogram (range, 1-15 years). Using linear regression with change in percent density as the outcome, we found that in women who did not go on to be diagnosed with breast cancer, change in percent density decreased as time between first and second mammogram increased (β = -1.62% per year, p = 0.004). However, in women who did go on to be diagnosed with breast cancer, there was no overall change in percent density associated with time between first and second mammogram (β = 0.29% per year, p = 0.61); the change over time was statistically significantly different between cases versus controls (p <0.009). If replicated in larger cohorts, these results suggest that within-individual changes in mammographic density as measured by percent density may be a useful biomarker of breast cancer risk.

  11. Panuveal malignant mesenchymoma.

    PubMed

    Pe'er, J; Neudorfer, M; Ron, N; Anteby, I; Lazar, M; Rosenmann, E

    1995-09-01

    Intraocular malignant mesenchymal tumors are very rare, and only a few case reports of such primary and metastatic tumors have been reported. We report a case of a malignant mesenchymoma involving the entire uveal tract. A 21-year-old woman presented with a tumor on the whole iris of the right eye, which caused intractable glaucoma. Upon enucleation of the eye, a very anaplastic tumor was found to occupy the whole uveal tract; its features were compatible with a tumor of mesenchymal origin, including rhabdomyosarcomatous and liposarcomatous characteristics. Choroidal osteoma was a coincidental finding. The histologic findings of the tumor were of two types of malignant mesenchymal tumors, and therefore the diagnosis of malignant mesenchymoma was made. This is to our knowledge the first tumor of its kind to be reported intraocularly. PMID:7668945

  12. The Malignant Protein Puzzle.

    PubMed

    Walker, Lary C; Jucker, Mathias

    2016-01-01

    When most people hear the words malignant and brain, cancer immediately comes to mind. But our authors argue that proteins can be malignant too, and can spread harmfully through the brain in neurodegenerative diseases that include Alzheimer's, Parkinson's, CTE, and ALS. Studying how proteins such as PrP, amyloid beta, tau, and others aggregate and spread, and kill brain cells, represents a crucial new frontier in neuroscience. PMID:27408676

  13. Wave optics-based LEO-LEO radio occultation retrieval

    NASA Astrophysics Data System (ADS)

    Benzon, Hans-Henrik; Høeg, Per

    2016-06-01

    This paper describes the theory for performing retrieval of radio occultations that use probing frequencies in the XK and KM band. Normally, radio occultations use frequencies in the L band, and GPS satellites are used as the transmitting source, and the occultation signals are received by a GPS receiver on board a Low Earth Orbit (LEO) satellite. The technique is based on the Doppler shift imposed, by the atmosphere, on the signal emitted from the GPS satellite. Two LEO satellites are assumed in the occultations discussed in this paper, and the retrieval is also dependent on the decrease in the signal amplitude caused by atmospheric absorption. The radio wave transmitter is placed on one of these satellites, while the receiver is placed on the other LEO satellite. One of the drawbacks of normal GPS-based radio occultations is that external information is needed to calculate some of the atmospheric products such as the correct water vapor content in the atmosphere. These limitations can be overcome when a proper selected range of high-frequency waves are used to probe the atmosphere. Probing frequencies close to the absorption line of water vapor have been included, thus allowing the retrieval of the water vapor content. Selecting the correct probing frequencies would make it possible to retrieve other information such as the content of ozone. The retrieval is performed through a number of processing steps which are based on the Full Spectrum Inversion (FSI) technique. The retrieval chain is therefore a wave optics-based retrieval chain, and it is therefore possible to process measurements that include multipath. In this paper simulated LEO to LEO radio occultations based on five different frequencies are used. The five frequencies are placed in the XK or KM frequency band. This new wave optics-based retrieval chain is used on a number of examples, and the retrieved atmospheric parameters are compared to the parameters from a global European Centre for Medium

  14. Increased COX-2 expression in epithelial and stromal cells of high mammographic density tissues and in a xenograft model of mammographic density.

    PubMed

    Chew, G L; Huo, C W; Huang, D; Hill, P; Cawson, J; Frazer, H; Hopper, J L; Haviv, I; Henderson, M A; Britt, K; Thompson, E W

    2015-08-01

    Mammographic density (MD) adjusted for age and body mass index is one of the strongest known risk factors for breast cancer. Given the high attributable risk of MD for breast cancer, chemoprevention with a safe and available agent that reduces MD and breast cancer risk would be beneficial. Cox-2 has been implicated in MD-related breast cancer risk, and was increased in stromal cells in high MD tissues in one study. Our study assessed differential Cox-2 expression in epithelial and stromal cells in paired samples of high and low MD human breast tissue, and in a validated xenograft biochamber model of MD. We also examined the effects of endocrine treatment upon Cox-2 expression in high and low MD tissues in the MD xenograft model. Paired high and low MD human breast tissue samples were immunostained for Cox-2, then assessed for differential expression and staining intensity in epithelial and stromal cells. High and low MD human breast tissues were separately maintained in biochambers in mice treated with Tamoxifen, oestrogen or placebo implants, then assessed for percentage Cox-2 staining in epithelial and stromal cells. Percentage Cox-2 staining was greater for both epithelial (p = 0.01) and stromal cells (p < 0.0001) of high compared with low MD breast tissues. In high MD biochamber tissues, percentage Cox-2 staining was greater in stromal cells of oestrogen-treated versus placebo-treated tissues (p = 0.05).

  15. Computing mammographic density from a multiple regression model constructed with image-acquisition parameters from a full-field digital mammographic unit

    NASA Astrophysics Data System (ADS)

    Lu, Lee-Jane W.; Nishino, Thomas K.; Khamapirad, Tuenchit; Grady, James J.; Leonard, Morton H., Jr.; Brunder, Donald G.

    2007-08-01

    Breast density (the percentage of fibroglandular tissue in the breast) has been suggested to be a useful surrogate marker for breast cancer risk. It is conventionally measured using screen-film mammographic images by a labor-intensive histogram segmentation method (HSM). We have adapted and modified the HSM for measuring breast density from raw digital mammograms acquired by full-field digital mammography. Multiple regression model analyses showed that many of the instrument parameters for acquiring the screening mammograms (e.g. breast compression thickness, radiological thickness, radiation dose, compression force, etc) and image pixel intensity statistics of the imaged breasts were strong predictors of the observed threshold values (model R2 = 0.93) and %-density (R2 = 0.84). The intra-class correlation coefficient of the %-density for duplicate images was estimated to be 0.80, using the regression model-derived threshold values, and 0.94 if estimated directly from the parameter estimates of the %-density prediction regression model. Therefore, with additional research, these mathematical models could be used to compute breast density objectively, automatically bypassing the HSM step, and could greatly facilitate breast cancer research studies.

  16. Probing Pluto's Atmosphere Using Ground-Based Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Sicardy, Bruno; Rio de Janeiro Occultation Team, Granada Team, International Occultation and Timing Association, Royal Astronomical Society New Zealand Occultation Section, Lucky Star associated teams

    2016-10-01

    Over the last three decades, some twenty stellar occultations by Pluto have been monitored from Earth. They occur when the dwarf planet blocks the light from a star for a few minutes as it moves on the sky. Such events led to the hint of a Pluto's atmosphere in 1985, that was fully confirmed during another occultation in 1988, but it was only in 2002 that a new occultation could be recorded. From then on, the dwarf planet started to move in front of the galactic center, which amplified by a large factor the number of events observable per year.Pluto occultations are essentially refractive events during which the stellar rays are bent by the tenuous atmosphere, causing a gradual dimming of the star. This provides the density, pressure and temperature profiles of the atmosphere from a few kilometers above the surface up to about 250 km altitude, corresponding respectively to pressure levels of about 10 and 0.1 μbar. Moreover, the extremely fine spatial resolution (a few km) obtained through this technique allows the detection of atmospheric gravity waves, and permits in principle the detection of hazes, if present.Several aspects make Pluto stellar occultations quite special: first, they are the only way to probe Pluto's atmosphere in detail, as the dwarf planet is far too small on the sky and the atmosphere is far too tenuous to be directly imaged from Earth. Second, they are an excellent example of participative science, as many amateurs have been able to record those events worldwide with valuable scientific returns, in collaboration with professional astronomers. Third, they reveal Pluto's climatic changes on decade-scales and constrain the various seasonal models currently explored.Finally, those observations are fully complementary to space exploration, in particular with the New Horizons (NH) mission. I will show how ground-based occultations helped to better calibrate some NH profiles, and conversely, how NH results provide some key boundary conditions

  17. Advanced Electrocardiography Can Identify Occult Cardiomyopathy in Doberman Pinschers

    NASA Technical Reports Server (NTRS)

    Spiljak, M.; Petric, A. Domanjko; Wilberg, M.; Olsen, L. H.; Stepancic, A.; Schlegel, T. T.; Starc, V.

    2011-01-01

    Recently, multiple advanced resting electrocardiographic (A-ECG) techniques have improved the diagnostic value of short-duration ECG in detection of dilated cardiomyopathy (DCM) in humans. This study investigated whether 12-lead A-ECG recordings could accurately identify the occult phase of DCM in dogs. Short-duration (3-5 min) high-fidelity 12-lead ECG recordings were obtained from 31 privately-owned, clinically healthy Doberman Pinschers (5.4 +/- 1.7 years, 11/20 males/females). Dogs were divided into 2 groups: 1) 19 healthy dogs with normal echocardiographic M-mode measurements: left ventricular internal diameter in diastole (LVIDd . 47mm) and in systole (LVIDs . 38mm) and normal 24-hour ECG recordings (<50 ventricular premature complexes, VPCs); and 2) 12 dogs with occult DCM: 11/12 dogs had increased M-mode measurements (LVIDd . 49mm and/or LVIDs . 40mm) and 5/11 dogs had also >100 VPCs/24h; 1/12 dogs had only abnormal 24-hour ECG recordings (>100 VPCs/24h). ECG recordings were evaluated via custom software programs to calculate multiple parameters of high-frequency (HF) QRS ECG, heart rate variability, QT variability, waveform complexity and 3-D ECG. Student's t-tests determined 19 ECG parameters that were significantly different (P < 0.05) between groups. Principal component factor analysis identified a 5-factor model with 81.4% explained variance. QRS dipolar and non-dipolar voltages, Cornell voltage criteria and QRS waveform residuum were increased significantly (P < 0.05), whereas mean HF QRS amplitude was decreased significantly (P < 0.05) in dogs with occult DCM. For the 5 selected parameters the prediction of occult DCM was performed using a binary logistic regression model with Chi-square tested significance (P < 0.01). ROC analyses showed that the five selected ECG parameters could identify occult ECG with sensitivity 89% and specificity 83%. Results suggest that 12-lead A-ECG might improve diagnostic value of short-duration ECG in earlier detection

  18. Error analysis for mesospheric temperature profiling by absorptive occultation sensors

    NASA Astrophysics Data System (ADS)

    Rieder, M. J.; Kirchengast, G.

    2001-01-01

    An error analysis for mesospheric profiles retrieved from absorptive occultation data has been performed, starting with realistic error assumptions as would apply to intensity data collected by available high-precision UV photodiode sensors. Propagation of statistical errors was investigated through the complete retrieval chain from measured intensity profiles to atmospheric density, pressure, and temperature profiles. We assumed unbiased errors as the occultation method is essentially self-calibrating and straight-line propagation of occulted signals as we focus on heights of 50 100 km, where refractive bending of the sensed radiation is negligible. Throughout the analysis the errors were characterized at each retrieval step by their mean profile, their covariance matrix and their probability density function (pdf). This furnishes, compared to a variance-only estimation, a much improved insight into the error propagation mechanism. We applied the procedure to a baseline analysis of the performance of a recently proposed solar UV occultation sensor (SMAS Sun Monitor and Atmospheric Sounder) and provide, using a reasonable exponential atmospheric model as background, results on error standard deviations and error correlation functions of density, pressure, and temperature profiles. Two different sensor photodiode assumptions are discussed, respectively, diamond diodes (DD) with 0.03% and silicon diodes (SD) with 0.1% (unattenuated intensity) measurement noise at 10 Hz sampling rate. A factor-of-2 margin was applied to these noise values in order to roughly account for unmodeled cross section uncertainties. Within the entire height domain (50 100 km) we find temperature to be retrieved to better than 0.3 K (DD) / 1 K (SD) accuracy, respectively, at 2 km height resolution. The results indicate that absorptive occultations acquired by a SMAS-type sensor could provide mesospheric profiles of fundamental variables such as temperature with unprecedented accuracy and

  19. Association of preS/S Mutations with Occult Hepatitis B Virus (HBV) Infection in South Korea: Transmission Potential of Distinct Occult HBV Variants.

    PubMed

    Kim, Hong; Kim, Bum-Joon

    2015-06-15

    Occult hepatitis B virus infection (HBV) is characterized by HBV DNA positivity but HBV surface antigen (HBsAg) negativity. Occult HBV infection is associated with a risk of HBV transmission through blood transfusion, hemodialysis, and liver transplantation. Furthermore, occult HBV infection contributes to the development of cirrhosis and hepatocellular carcinoma. We recently reported the characteristic molecular features of mutations in the preS/S regions among Korean individuals with occult infections caused by HBV genotype C2; the variants of preS and S related to severe liver diseases among chronically infected patients were also responsible for the majority of HBV occult infections. We also reported that HBsAg variants from occult-infected Korean individuals exhibit lower HBsAg secretion capacity but not reduced HBV DNA levels. In addition, these variants exhibit increased ROS-inducing capacity compared with the wild-type strain, linking HBV occult infections to liver cell damage. Taken together, our previous reports suggest the transmission potential of distinct HBV occult infection-related variants in South Korea.

  20. Feature and Contrast Enhancement of Mammographic Image Based on Multiscale Analysis and Morphology

    PubMed Central

    Wu, Shibin; Xie, Yaoqin

    2013-01-01

    A new algorithm for feature and contrast enhancement of mammographic images is proposed in this paper. The approach bases on multiscale transform and mathematical morphology. First of all, the Laplacian Gaussian pyramid operator is applied to transform the mammography into different scale subband images. In addition, the detail or high frequency subimages are equalized by contrast limited adaptive histogram equalization (CLAHE) and low-pass subimages are processed by mathematical morphology. Finally, the enhanced image of feature and contrast is reconstructed from the Laplacian Gaussian pyramid coefficients modified at one or more levels by contrast limited adaptive histogram equalization and mathematical morphology, respectively. The enhanced image is processed by global nonlinear operator. The experimental results show that the presented algorithm is effective for feature and contrast enhancement of mammogram. The performance evaluation of the proposed algorithm is measured by contrast evaluation criterion for image, signal-noise-ratio (SNR), and contrast improvement index (CII). PMID:24416072

  1. False positive reduction in mammographic mass detection using local binary patterns.

    PubMed

    Oliver, Arnau; Lladó, Xavier; Freixenet, Jordi; Martí, Joan

    2007-01-01

    In this paper we propose a new approach for false positive reduction in the field of mammographic mass detection. The goal is to distinguish between the true recognized masses and the ones which actually are normal parenchyma. Our proposal is based on Local Binary Patterns (LBP) for representing salient micro-patterns and preserving at the same time the spatial structure of the masses. Once the descriptors are extracted, Support Vector Machines (SVM) are used for classifying the detected masses. We test our proposal using a set of 1792 suspicious regions of interest extracted from the DDSM database. Exhaustive experiments illustrate that LBP features are effective and efficient for false positive reduction even at different mass sizes, a critical aspect in mass detection systems. Moreover, we compare our proposal with current methods showing that LBP obtains better performance. PMID:18051070

  2. Mammographic Imaging Studies Using the Monte Carlo Image Simulation-Differential Sampling (MCMIS-DS) Code

    SciTech Connect

    Kuruvilla Verghese

    2002-04-05

    This report summarizes the highlights of the research performed under the 1-year NEER grant from the Department of Energy. The primary goal of this study was to investigate the effects of certain design changes in the Fisher Senoscan mammography system and in the degree of breast compression on the discernability of microcalcifications in calcification clusters often observed in mammograms with tumor lesions. The most important design change that one can contemplate in a digital mammography system to improve resolution of calcifications is the reduction of pixel dimensions of the digital detector. Breast compression is painful to the patient and is though to be a deterrent to women to get routine mammographic screening. Calcification clusters often serve as markers (indicators ) of breast cancer.

  3. New insights to occult gastrointestinal bleeding: From pathophysiology to therapeutics

    PubMed Central

    Sánchez-Capilla, Antonio Damián; De La Torre-Rubio, Paloma; Redondo-Cerezo, Eduardo

    2014-01-01

    Obscure gastrointestinal bleeding is still a clinical challenge for gastroenterologists. The recent development of novel technologies for the diagnosis and treatment of different bleeding causes has allowed a better management of patients, but it also determines the need of a deeper comprehension of pathophysiology and the analysis of local expertise in order to develop a rational management algorithm. Obscure gastrointestinal bleeding can be divided in occult, when a positive occult blood fecal test is the main manifestation, and overt, when external sings of bleeding are visible. In this paper we are going to focus on overt gastrointestinal bleeding, describing the physiopathology of the most usual causes, analyzing the diagnostic procedures available, from the most classical to the novel ones, and establishing a standard algorithm which can be adapted depending on the local expertise or availability. Finally, we will review the main therapeutic options for this complex and not so uncommon clinical problem. PMID:25133028

  4. Status of the Transneptunian Automated Occultation Survey (TAOS II)

    NASA Astrophysics Data System (ADS)

    Lehner, Matthew; Wang, Shiang-Yu; Alcock, Charles; Reyes-Ruiz, Mauricio; Castro, Joel; Chen, Wen Ping; Chu, You-Hua; Cook, Kem H.; Geary, John C.; Huang, Chung-Kai; Kim, Dae-Won; Norton, Timothy; Szentgyorgyi, Andrew; Yen, WeiLing; Zhang, Zhi-Wei; Figueroa, Liliana

    2016-10-01

    The Transneptunian Automated Occultation Survey (TAOS II) will aim to detect occultations of stars by small (~1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare ($<0.001 events per star per year) and short in duration (~200 ms), so many stars must be monitored at a high readout cadence. TAOS II will operate three 1.3 meter telescopes at the Observatorio Astronomico Nacional at San Pedro Martir in Baja California, Mexico. With a 2.3 square degree field of view and a high speed camera comprising CMOS imagers, the survey will monitor 10,000 stars simultaneously with all three telescopes at a readout cadence of 20 Hz. Construction of the site began in the fall of 2013, and the survey will begin in the summer of 2017. This poster will provide an update on the status of the survey development and the schedule leading to the beginning of survey operations.

  5. Intra-day Investigation of Pluto's Atmosphere with Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Person, Michael J.; Bosh, Amanda S.; Levine, Stephen

    2014-02-01

    To monitor Pluto's evolving atmosphere, and search for atmospheric variations on timescales shorter than one Pluto day, we propose to observe four Pluto stellar occultations all occurring in the last eight days of July. Two of the events are visible from Australia on the night of 23 July 2014 UT, and two are visible from Chile on 27 July and 31 July 2014. The coincidence of these occultations in time provides a rare opportunity to search for short-timescale changes in Pluto's atmosphere, in addition to allowing us to continue our annual monitoring of Pluto's atmospheric evolution. Recent transport models (Young 2013) have brought long-standing assertions about Pluto's atmospheric evolution into question, implying the possibility that Pluto's atmosphere does not collapse for much of each revolution as previously thought (Hansen and Paige 1996). The current epoch is when these competing models begin to diverge and continuing data collection is necessary to distinguish among the various models.

  6. Digital solar edge tracker for the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Mauldin, L. E., III; Moore, A. S.; Stump, C. W.; Mayo, L. S.

    1987-01-01

    The optical and electronic design of the Halogen Occultation Experiment (Haloe) elevation sun sensor is described. The Haloe instrument is a gas-correlation radiometer now being developed at NASA Langley for the Upper Atmosphere Research Satellite. The system uses a Galilean telescope to form a solar image on a linear silicon photodiode array. The array is a self-scanned monolithic CCD. The addresses of both solar edges imaged on the array are used by the control/pointing system to scan the Haloe science instantaneous field of view (IFOV) across the vertical solar diameter during instrument calibration and then to maintain the science IFOV 4 arcmin below the top edge during the science data occultation event. Vertical resolution of 16 arcsec and a radiometric dynamic range of 100 are achieved at the 700-nm operating wavelength. The design provides for loss of individual photodiode elements without loss of angular tracking capability.

  7. Titan's haze as seen by VIMS during solar occultation observations

    NASA Astrophysics Data System (ADS)

    Sotin, Christophe; Lawrence, Ken; Xu, Fang; West, Robert; Brown, Robert; Baines, Kevin; Buratti, Bonnie; Clark, Roger; Micholson, Phil

    2016-06-01

    This study describe solar occultation observations of Titan's atmosphere by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft. These observations include two recent observations made in the last few months. The solar occultation observations have been made at different latitudes and seasons, which allows us to investigate the variability of the density profile of aerosols. We present the line curves in the different atmospheric windows, and the data processing and the inversion method to retrieve vertical density profile. This unique data set provides information on Titan's opacity in the atmospheric windows, which is important to retrieve the surface properties. It also provides information on the cross-subsection of the aerosols as a function of wavelength in the wavelength range 1 to 5 micron.

  8. Advancing Technology for Starlight Suppression via an External Occulter

    NASA Technical Reports Server (NTRS)

    Kasdin, N. J.; Spergel, D. N.; Vanderbei, R. J.; Lisman, D.; Shaklan, S.; Thomson, M.; Walkemeyer, P.; Bach, V.; Oakes, E.; Cady, E.; Martin, S.; Marchen, L.; Macintosh, B.; Rudd, R. E.; Mikula, J.; Lynch, D.

    2011-01-01

    External occulters provide the starlight suppression needed for detecting and characterizing exoplanets with a much simpler telescope and instrument than is required for the equivalent performing coronagraph. In this paper we describe progress on our Technology Development for Exoplanet Missions project to design, manufacture, and measure a prototype occulter petal. We focus on the key requirement of manufacturing a precision petal while controlling its shape within precise tolerances. The required tolerances are established by modeling the effect that various mechanical and thermal errors have on scatter in the telescope image plane and by suballocating the allowable contrast degradation between these error sources. We discuss the deployable starshade design, representative error budget, thermal analysis, and prototype manufacturing. We also present our meteorology system and methodology for verifying that the petal shape meets the contrast requirement. Finally, we summarize the progress to date building the prototype petal.

  9. Atmosphere sounding by GPS radio occultation: First results from CHAMP

    NASA Astrophysics Data System (ADS)

    Wickert, Jens; Reigber, Christoph; Beyerle, Georg; König, Rolf; Marquardt, Christian; Schmidt, Torsten; Grunwaldt, Ludwig; Galas, Roman; Meehan, Thomas K.; Melbourne, William G.; Hocke, Klemens

    The first radio occultation measurements of the CHAMP (CHAllenging Minisatellite Payload) satellite using Global Positioning System (GPS) signals have been performed on February 11, 2001. By the end of April 2001 more than 3000 occultations were recorded. Globally distributed vertical profiles of dry temperature and specific humidity are derived, of which a set of 438 vertical dry temperature profiles is compared with corresponding global weather analyses. The observed temperature bias is less than ∼1 K above the tropopause and even less than 0.5 K in the altitude interval from 12 to 20 km at latitudes >30°N. About 55% of the compared profiles reached the last kilometer above the Earth's surface. In spite of the activated anti-spoofing mode of the GPS system the state-of-the-art GPS flight receiver aboard CHAMP combined with favorable antenna characteristics allows for atmospheric sounding with high accuracy and vertical resolution.

  10. Mammographic density, parity and age at first birth, and risk of breast cancer: an analysis of four case-control studies.

    PubMed

    Woolcott, Christy G; Koga, Karin; Conroy, Shannon M; Byrne, Celia; Nagata, Chisato; Ursin, Giske; Vachon, Celine M; Yaffe, Martin J; Pagano, Ian; Maskarinec, Gertraud

    2012-04-01

    Mammographic density is strongly and consistently associated with breast cancer risk. To determine if this association was modified by reproductive factors (parity and age at first birth), data were combined from four case-control studies conducted in the United States and Japan. To overcome the issue of variation in mammographic density assessment among the studies, a single observer re-read all the mammograms using one type of interactive thresholding software. Logistic regression was used to estimate odds ratios (OR) while adjusting for other known breast cancer risk factors. Included were 1,699 breast cancer cases and 2,422 controls, 74% of whom were postmenopausal. A positive association between mammographic density and breast cancer risk was evident in every group defined by parity and age at first birth (OR per doubling of percent mammographic density ranged between 1.20 and 1.39). Nonetheless, the association appeared to be stronger among nulliparous than parous women (OR per doubling of percent mammographic density = 1.39 vs. 1.24; P interaction = 0.054). However, when examined by study location, the effect modification by parity was apparent only in women from Hawaii and when examined by menopausal status, it was apparent in postmenopausal, but not premenopausal, women. Effect modification by parity was not significant in subgroups defined by body mass index or ethnicity. Adjusting for mammographic density did not attenuate the OR for the association between parity and breast cancer risk by more than 16.4%, suggesting that mammographic density explains only a small proportion of the reduction in breast cancer risk associated with parity. In conclusion, this study did not support the hypothesis that parity modifies the breast cancer risk attributed to mammographic density. Even though an effect modification was found in Hawaiian women, no such thing was found in women from the other three locations.

  11. Fluorescence staging laparoscopy for gastrointestinal malignancies: experimental experience

    NASA Astrophysics Data System (ADS)

    Prosst, Ruediger L.; Pietschmann, Mathias; Rheinwald, Markus; Haase, Thomas; Herfarth, Christian; Gahlen, Johannes

    2001-01-01

    Accurate staging can be a major problem in therapeutic planning of advanced abdominal malignancies. We experimentally combined conventional staging laparoscopy with aminolevulinic acid (ALA) induced fluorescence diagnosis (FD) to improve the detection of disseminated peritoneal tumors. Using different photosensitization times and ALA concentrations we evaluated the optimal fluorescence parameters for laparoscopic fluorescence diagnosis of intra abdominal tumor spread. In a rat tumor model we performed conventional and fluorescence laparoscopy to determine the increase of sensitivity gained by FD in terms of additionally detected lesions. After laparoscopic examination, the fluorescence emission from the tumors was spectrometically analyzed. Serum levels of ALA and PpIX were measured by HPLC to determine their systemic metabolism. Fluorescence staging laparoscopy was able to visualize even macroscopically occult neoplasms. Using 1.5 percent ALA solution and a photosensitization time of 4 hours as favorable parameters the diagnostic value of conventional staging laparoscopy was significantly improved: 35 percent of all malignant lesions were detected only by FD. Therefore, fluorescence laparoscopy suggest to be a highly promising preoperative staging tool requiring minimal technical and clinical expenditure. It provides the laparoscopist with a rapid and accurate technique to assess more thoroughly the full extent of malignant tumor growth in the abdominal cavity.

  12. Assessment of change in breast density: reader performance using synthetic mammographic images

    NASA Astrophysics Data System (ADS)

    Astley, Sue; Swayamprakasam, Chitra; Berks, Michael; Sergeant, Jamie; Morris, Julie; Wilson, Mary; Barr, Nicky; Boggis, Caroline

    2012-02-01

    A recent study has shown that breast cancer risk can be reduced by taking Tamoxifen, but only if this results in at least a 10% point reduction in mammographic density. When mammographic density is quantified visually, it is impossible to assess reader accuracy using clinical images as the ground truth is unknown. Our aim was to compare three models of assessing density change and to determine reader accuracy in identifying reductions of 10% points or more. We created 100 synthetic, mammogram-like images comprising 50 pairs designed to simulate natural reduction in density within each pair. Model I: individual images were presented to readers and density assessed. Model II: pairs of images were displayed together, with readers assessing density for each image. Model III: pairs of images were displayed together, and readers asked whether there was at least a 10% point reduction in density. Ten expert readers participated. Readers' estimates of percentage density were significantly closer to the truth (6.8%-26.4%) when images were assessed individually rather than in pairs (9.6%-29.8%). Measurement of change was significantly more accurate in Model II than Model I (p<0.005). Detecting density changes of at least 10% points in image pairs, mean accuracy was significantly (p<0.005) lower (58%-88%) when change was calculated from density assessments than in Model III (74%-92%). Our results suggest that where readers need to identify change in density, images should be displayed alongside one another. In our study, less accurate assessors performed better when asked directly about the magnitude of the change.

  13. Glycemic index, glycemic load and mammographic breast density: the EPIC Florence longitudinal study.

    PubMed

    Masala, Giovanna; Assedi, Melania; Bendinelli, Benedetta; Ermini, Ilaria; Occhini, Daniela; Sieri, Sabina; Brighenti, Furio; Del Turco, Marco Rosselli; Ambrogetti, Daniela; Palli, Domenico

    2013-01-01

    A few studies have evaluated the association between diet and mammographic breast density (MBD) and results are inconsistent. MBD, a well-recognized risk factor for breast cancer, has been proposed as a marker of cumulative exposure to hormones and growth factors. Diets with a high glycemic index (GI) or glycemic load (GL) may increase breast cancer risk, via an effect on the insulin-like growth factor axis. We have investigated the association between carbohydrate intake, GI, GL and MBD in a prospective study. We identified a large series of women, in the frame of the EPIC-Florence cohort, with a mammogram taken five years after enrolment, when detailed information on dietary and lifestyle habits and anthropometric measurements had been collected. Mammograms have been retrieved (1,668, 83%) and MBD assessed according to Wolfe's classification. We compared women with high MBD (P2+DY Wolfe's categories) with those with low MBD (N1+P1) through logistic models adjusted for age, education, body mass index, menopause, number of children, breast feeding, physical activity, non-alcohol energy, fibers, saturated fat and alcohol. A direct association between GL and high MBD emerged in the highest quintile of intake in comparison with the lowest quintile (OR = 1.73, 95%CI 1.13-2.67, p for trend = 0.048) while no association with glycemic index was evident. These results were confirmed after exclusion of women reporting to be on a diet or affected with diabetes, and when Hormone Replacement Therapy at the date of mammographic examination used to assess MBD was considered. The effect was particularly evident among leaner women, although no interaction was found. A positive association was suggested for increasing simple sugar and total carbohydrates intakes limited to the highest quintiles. In this Italian population we observed an association between glycemic load, total and rapidly absorbed carbohydrates and high MBD. These novel results warrant further investigations. PMID

  14. An assessment of reference exposure in analogic and digital mammographic units

    NASA Astrophysics Data System (ADS)

    Tilly, J. G.; Miguel, C.; Schelin, H. R.; Porto, L. E.; Paschuk, S.; Denyak, V.; Kmiecik, C.

    2014-11-01

    In this study, the incident air kerma (Ki,a), half-value layer (HVL), output and voltage accuracy for 28 mammography services were evaluated. All mammographs had high frequency rectification, a focus-film distance greater than 60 cm, automatic exposure control, a Mo-Mo anode-filter combination, and compression system. Twenty-three evaluations were made of analogic imaging systems and 21 of digital imaging systems, two of which were full field digital mammography units. The Ki,a was measured in the beam radiation with a 6 cm3 ionization chamber, calibrated for a mammography range of energy. A standard American College of Radiology mammographic phantom simulated a skull caudal incidence. The average, minimum, and maximum Ki,a values were 10.13 mGy, 3.92 mGy, and 30.41 mGy, respectively. However, when the analogic and digital systems are analyzed separately in two subsets, the values were 8.13 mGy, 3.92 mGy, and 11.78 mGy for the analogic systems and 12.33 mGy, 5.21 mGy, and 30.41 mGy for the digital systems, respectively. The results show that the Ki,a values found in digital systems were higher than those in analogic systems, highlighting the differences between these acquisition systems. All HVL values, measured in the primary beam at 28 kV were found between 0.33 mm Al and 0.43 mm Al. Although the manufacture time of the equipment was approximately 146 months (~12 years) prior, the variation in output was between 0.071 mGy/mAs and 0.164 mGy/mAs for the entire sample.

  15. A completely automated CAD system for mass detection in a large mammographic database

    SciTech Connect

    Bellotti, R.; De Carlo, F.; Tangaro, S.

    2006-08-15

    Mass localization plays a crucial role in computer-aided detection (CAD) systems for the classification of suspicious regions in mammograms. In this article we present a completely automated classification system for the detection of masses in digitized mammographic images. The tool system we discuss consists in three processing levels: (a) Image segmentation for the localization of regions of interest (ROIs). This step relies on an iterative dynamical threshold algorithm able to select iso-intensity closed contours around gray level maxima of the mammogram. (b) ROI characterization by means of textural features computed from the gray tone spatial dependence matrix (GTSDM), containing second-order spatial statistics information on the pixel gray level intensity. As the images under study were recorded in different centers and with different machine settings, eight GTSDM features were selected so as to be invariant under monotonic transformation. In this way, the images do not need to be normalized, as the adopted features depend on the texture only, rather than on the gray tone levels, too. (c) ROI classification by means of a neural network, with supervision provided by the radiologist's diagnosis. The CAD system was evaluated on a large database of 3369 mammographic images [2307 negative, 1062 pathological (or positive), containing at least one confirmed mass, as diagnosed by an expert radiologist]. To assess the performance of the system, receiver operating characteristic (ROC) and free-response ROC analysis were employed. The area under the ROC curve was found to be A{sub z}=0.783{+-}0.008 for the ROI-based classification. When evaluating the accuracy of the CAD against the radiologist-drawn boundaries, 4.23 false positives per image are found at 80% of mass sensitivity.

  16. All-Sky Earth Occultation Observations with the Fermi Gamma-Ray Burst Monitor

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, C. A.; Beklen, E.; Bhat, P. N.; Briggs, M.; Camero-Arranz, A.; Case, G.; Jenke, P.; Chaplin, V.; Cherry, M.; Connaughton, V.; Finger, M.; Haynes, R. H.; Preece, R.; Rodi, J.

    2009-01-01

    Using the Gamma Ray Burst Monitor (GBM) on-board Fermi, we are monitoring the hard X-ray/ soft gamma ray sky using the Earth occultation technique. Each time a source in our catalog is occulted by (or exits occultation by) the Earth, we measure its flux using the change in count rates due to the occultation. Currently we are using CTIME data with 8 energy channels spanning 8 keV to 1 MeV for the GBM NaI detectors and spanning 150 keV to 40 MeV for the GBM BGO detectors. Our preliminary catalog consists of galactic X-ray binaries, the Crab Nebula, and active galactic nuclei. In addition, to Earth occultations, we have observed numerous occultations with Fermi's solar panels.

  17. Primary Malignant Tumours of Bone Following Previous Malignancy

    PubMed Central

    Patton, J. T.; Sommerville, S. M. M.; Grimer, R. J.

    2008-01-01

    Destructive bone lesions occurring in patients who have previously had a malignancy are generally assumed to be a metastasis from that malignancy. We reviewed 60 patients with a previous history of malignancy, who presented with a solitary bone lesion that was subsequently found to be a new and different primary sarcoma of bone. These second malignancies occurred in three distinct groups of patients: (1) patients with original tumours well known to be associated with second malignancies (5%); (2) patients whose second malignancies were likely to be due to the previous treatment of their primary malignancy (40%); (3) patients in whom there was no clearly defined association between malignancies (55%). The purpose of this study is to emphasise the necessity for caution in assuming the diagnosis of a metastasis when a solitary bone lesion is identified following a prior malignancy. Inappropriate biopsy and treatment of primary bone sarcomas compromises limb salvage surgery and can affect patient mortality. PMID:18414590

  18. Occult orbital neuroblastoma detected after administration of an antitumor vaccine.

    PubMed

    Wilson, Matthew W; Moshfeghi, Darius M; Haik, Barrett G; Haight, Ann E; Hill, D Ashley; Davidoff, Andrew M; Rousseau, Raphael F; Bowman, Laura C

    2003-01-01

    A 6-year-old girl with neuroblastoma developed swelling and erythema of her right upper eyelid following administration of an interleukin-2 and lymphotactin gene-modified allogeneic neuroblastoma cell vaccine. Computed tomography demonstrated a cystic lesion in the subperiosteal space. A biopsy of the mass showed necrotic neuroblastoma with minimal associated inflammation. To our knowledge, this case represents the first description of occult orbital metastases in a patient with neuroblastoma detected after administration of an antitumor vaccine.

  19. Occultation Predictions Using CCD Strip-Scanning Astrometry

    NASA Technical Reports Server (NTRS)

    Dunham, Edward W.; Ford, C. H.; Stone, R. P. S.; McDonald, S. W.; Olkin, C. B.; Elliot, J. L.; Witteborn, Fred C. (Technical Monitor)

    1994-01-01

    We are developing the method of CCD strip-scanning astrometry for the purpose of deriving reliable advance predictions for occultations involving small objects in the outer solar system. We are using a camera system based on a Ford/Loral 2Kx2K CCD with the Crossley telescope at Lick Observatory for this work. The columns of die CCD are aligned East-West, the telescope drive is stopped, and the CCD is clocked at the same rate that the stars drift across it. In this way we obtain arbitrary length strip images 20 arcmin wide with 0.58" pixels. Since planets move mainly in RA, it is possible to obtain images of the planet and star to be occulted on the same strip well before the occultation occurs. The strip-to-strip precision (i.e. reproducibility) of positions is limited by atmospheric image motion to about 0.1" rms per strip. However, for objects that are nearby in R.A., the image motion is highly correlated and their relative positions are good to 0.02" rms per strip. We will show that the effects of atmospheric image motion on a given strip can be removed if a sufficient number of strips of a given area have been obtained. Thus, it is possible to reach an rms precision of 0.02" per strip, corresponding to about 0.3 of Pluto or Triton's angular radius. The ultimate accuracy of a prediction based on strip-scanning astrometry is currently limited by the accuracy of the positions of the stars in the astrometric network used and by systematic errors most likely due to the optical system. We will show the results of . the prediction of some recent occultations as examples of the current capabilities and limitations of this technique.

  20. Lunar occultations of IRAS point sources, 1986-1990

    NASA Technical Reports Server (NTRS)

    Simon, M.; Chen, W. P.; Cassar, L.

    1986-01-01

    A complete listing is given for objects in the IRAS Point Source Catalog which will be occulted by the moon over the course of 1986-1990. A total of 14,148 ASCII card images is encompassed by the complete listing of objects having geocentric events during this period. The results contained in this complete listing are illustrated in two of the present tables for the brightest objects at 12 and 100 micron wavelengths.

  1. The Structure of Titan's Atmosphere from Cassini Radio Occultations

    NASA Technical Reports Server (NTRS)

    Schinder, Paul J.; Flasar, F. Michael; Marouf, Essam A.; French, Richard G.; McGhee, Colleen A.; Kliore, Arvydas J.; Rappaport, Nicole J.; Barbinis, Elias; Fleischman, Don; Anabtawi, Aseel

    2011-01-01

    We present results from the two radio occultations of the Cassini spacecraft by Titan in 2006, which probed mid-southern latitudes. Three of the ingress and egress soundings occurred within a narrow latitude range, 31.34 deg S near the surface, and the fourth at 52.8 deg S. Temperature - altitude profiles for all four occultation soundings are presented, and compared with the results of the Voyager 1 radio occultation (Lindal et al., 1983), the HASI instrument on the Huygens descent probe (Fulchignoni et al., 2005), and Cassini CIRS results (Flasar et al., 2005; Achterberg et al., 2008b). Sources of error in the retrieved temperature - altitude profiles are also discussed, and a major contribution is from spacecraft velocity errors in the reconstructed ephemeris. These can be reduced by using CIRS data at 300 km to make along-track adjustments of the spacecraft timing. The occultation soundings indicate that the temperatures just above the surface at 31-34 deg S are about 93 K, while that at 53 deg S is about 1 K colder. At the tropopause, the temperatures at the lower latitudes are all about 70 K, while the 53 deg S profile is again 1 K colder. The temperature lapse rate in the lowest 2 km for the two ingress (dawn) profiles at 31 and 33 deg S lie along a dry adiabat except within approximately 200m of the surface, where a small stable inversion occurs. This could be explained by turbulent mixing with low viscosity near the surface. The egress profile near 34 deg S shows a more complex structure in the lowest 2 km, while the egress profile at 53 deg S is more stable.

  2. [Reference standards in the performance of a mammographic screening program. Results of the screening program in the province of Florence, 1992].

    PubMed

    Ciatto, S; Bonardi, R; Rosselli del Turco, M

    1993-10-01

    The authors report the results of the Florence District program for the year 1992. 11,033 subjects were examined. Attendance rate (64.4%) was significantly related to age (42-49 = 71.0%; 50-59 = 66.7%; 60-70 = 58.5%). Recall rate to diagnostic assessment was 2.09% (mammographic abnormalities = 199, subjective symptoms other than pain = 32) and was related to age (42-49 = 3.12%; 50-59 = 1.65%; 60-70 = 1.77%). According to the results of diagnostic assessment 53 surgical biopsies (0.48%) were recommended and performed. The biopsy rate was also related to age (42-49 = 0.2%; 50-59 = 0.4%; 60-70 = 0.7%). Forty-seven carcinomas were detected in 46 subjects (benign/malignant biopsy ratio = 0.13). Cancer detection rate was 0.42% and changed significantly with age (42-49 = 0.13; 50-59 = 0.36; 60-70 = 0.68%), as well as the observed/expected cancer ratio (42-49 = 0.89; 50-59 = 2.03; 60-70 = 2.98). Detected cancers were nonpalpable in 57% of cases. Pathologic staging was pTIS in 2 cases, pT1a in 5, pT1b in 17, pT1c in 17, pT2 in 5, and pT4b in one case. Six of 47 (12.8%) cancers involved axillary nodes. A preliminary estimate of screening cost yielded a total cost of Lit. 397,671,000 for the year 1992--i.e., Lit. 36,000 per examined subject and Lit. 8,461,000 per detected cancer. The results are compared with reference standards for the evaluation of screening performance provided by the national breast screening program in the United Kingdom.

  3. Solar occultation with SCIAMACHY: First results and validation

    NASA Astrophysics Data System (ADS)

    Meyer, J.; Schlesier, A.; Rozanov, A.; Rozanov, V. V.; Bovensmann, H.; Burrows, J. P.

    2003-04-01

    SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) has successfully been launched onboard ENVISAT (ENVIronmental SATellite) in March 2002. It is measuring scattered, reflected, and direct radiation in the UV-Vis-IR range in three different viewing geometries (nadir, limb, and solar/lunar occultation). The focus of this presentation is on first solar occultation results. The retrieval algorithm is based on the optimal estimation method. It is specialised on the spectral fitting of differential structures of radiation transmitted through the atmosphere. Height resolved profiles of O_3, NO_2, O_2, and CO_2 were derived from the occultation data. O_3 and NO_2 as natural first scientific goals can be retrieved with considerable accuracy. First results of the validation activities will be shown. Retrieved profiles of O_2 and CO_2 are used to improve the information about tangent heights as they are well mixed constituents of the atmosphere and can also be calculated from pressure and temperature profiles.

  4. Lunar occultation observation of μ Sgr: A progress report

    SciTech Connect

    Jatmiko, A. T. P.; Puannandra, G. P.; Hapsari, R. D.; Putri, R. A.; Arifin, Z. M.; Haans, G. K.; Hadiputrawan, I. P. W.

    2014-03-24

    Lunar Occultation (LO) is an event where limb of the Moon passing over a particular heavenly bodies such as stars, asteroids, or planets. In other words, during the event, stars, asteroids and planets are occulted by the Moon. When occulted objects contact the lunar limb, there will be a diffraction fringe(s) which can be measured photometrically, until the signal vanishes into noise. This event will give us a valuable information about binarities (of stars) and/or angular diameters estimation (of stars, planets, asteroids) in milliarcsecond resolution, by fitting with theoretical LO pattern. CCDs are common for LO observation because of its fast read out, and recently are developed for sub-meter class telescope. In this paper, our LO observation attempt of μ Sgr and its progress report are presented. The observation was conducted on July 30{sup th}, 2012 at Bosscha Observatory, Indonesia, using 45cm f/12 GOTO telescope combined with ST-9 XE CCD camera and Bessel B filter. We used drift-scan method to obtain light curve of the star as it was disappearing behind Moon's dark limb. Our goal is to detect binarity (or multiplicity) of this particular object.

  5. Designing asymmetric and branched petals for planet-finding occulters.

    PubMed

    Cady, Eric; Kasdin, N J; Shaklan, Stuart

    2010-01-18

    One of the proposed methods for finding small extrasolar planets is through use of an occulter, a spacecraft which flies in formation with a space-based telescope to block the light from a star, while leaving nearby planets unaffected. This is accomplished by placing the occulter far enough from the telescope to give it a small angular size, and by carefully choosing the shape to strongly suppress the starlight at the telescope aperture. For most designs, this shape takes the form of a number of bilaterally-symmetric structures called petals, arrayed about a circular central disk. In this paper, we show that the necessary number of petals may be reduced by the introduction of an asymmetry in the petal shape, and describe a a general procedure for producing such a shape by optimization for any occulter with petals. In addition, we show that permitting openings within each petal allows a number of additional modifications to be made without affecting the suppression. PMID:20173872

  6. First tsunami gravity wave detection in ionospheric radio occultation data

    DOE PAGESBeta

    Coïsson, Pierdavide; Lognonné, Philippe; Walwer, Damian; Rolland, Lucie M.

    2015-05-09

    After the 11 March 2011 earthquake and tsunami off the coast of Tohoku, the ionospheric signature of the displacements induced in the overlying atmosphere has been observed by ground stations in various regions of the Pacific Ocean. We analyze here the data of radio occultation satellites, detecting the tsunami-driven gravity wave for the first time using a fully space-based ionospheric observation system. One satellite of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) recorded an occultation in the region above the tsunami 2.5 h after the earthquake. The ionosphere was sounded from top to bottom, thus providing themore » vertical structure of the gravity wave excited by the tsunami propagation, observed as oscillations of the ionospheric Total Electron Content (TEC). The observed vertical wavelength was about 50 km, with maximum amplitude exceeding 1 total electron content unit when the occultation reached 200 km height. We compared the observations with synthetic data obtained by summation of the tsunami-coupled gravity normal modes of the Earth/Ocean/atmosphere system, which models the associated motion of the ionosphere plasma. These results provide experimental constraints on the attenuation of the gravity wave with altitude due to atmosphere viscosity, improving the understanding of the propagation of tsunami-driven gravity waves in the upper atmosphere. They demonstrate that the amplitude of the tsunami can be estimated to within 20% by the recorded ionospheric data.« less

  7. First tsunami gravity wave detection in ionospheric radio occultation data

    SciTech Connect

    Coïsson, Pierdavide; Lognonné, Philippe; Walwer, Damian; Rolland, Lucie M.

    2015-05-09

    After the 11 March 2011 earthquake and tsunami off the coast of Tohoku, the ionospheric signature of the displacements induced in the overlying atmosphere has been observed by ground stations in various regions of the Pacific Ocean. We analyze here the data of radio occultation satellites, detecting the tsunami-driven gravity wave for the first time using a fully space-based ionospheric observation system. One satellite of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) recorded an occultation in the region above the tsunami 2.5 h after the earthquake. The ionosphere was sounded from top to bottom, thus providing the vertical structure of the gravity wave excited by the tsunami propagation, observed as oscillations of the ionospheric Total Electron Content (TEC). The observed vertical wavelength was about 50 km, with maximum amplitude exceeding 1 total electron content unit when the occultation reached 200 km height. We compared the observations with synthetic data obtained by summation of the tsunami-coupled gravity normal modes of the Earth/Ocean/atmosphere system, which models the associated motion of the ionosphere plasma. These results provide experimental constraints on the attenuation of the gravity wave with altitude due to atmosphere viscosity, improving the understanding of the propagation of tsunami-driven gravity waves in the upper atmosphere. They demonstrate that the amplitude of the tsunami can be estimated to within 20% by the recorded ionospheric data.

  8. Lunar occultation of Saturn. IV - Astrometric results from observations of the satellites

    NASA Technical Reports Server (NTRS)

    Dunham, D. W.; Elliot, J. L.

    1978-01-01

    The method of determining local lunar limb slopes, and the consequent time scale needed for diameter studies, from accurate occultation timings at two nearby telescopes is described. Results for photoelectric observations made at Mauna Kea Observatory during the occultation of Saturn's satellites on March 30, 1974, are discussed. Analysis of all observations of occultations of Saturn's satellites during 1974 indicates possible errors in the ephemerides of Saturn and its satellites.

  9. Hemostasis and malignancy.

    PubMed

    Francis, J L; Biggerstaff, J; Amirkhosravi, A

    1998-01-01

    There is considerable evidence that the hemostatic system is involved in the growth and spread of malignant disease. There is an increased incidence of thromboembolic disease in patients with cancers and hemostatic abnormalities are extremely common in such patients. Antihemostatic agents have been successfully used to treat a variety of experimental tumors, and several clinical trials in humans have been initiated. Although metastasis is undoubtedly multifactorial, intravascular coagulation activation and peritumor fibrin deposition seem to be important. The mechanisms by which hemostatic activation facilitates the malignant process remain to be completely elucidated. Of central importance may be the presence on malignant cells of tissue factor and urokinase receptor. Recent studies have suggested that these proteins, and others, may be involved at several stages of metastasis, including the key event of neovascularization. Tissue factor, the principal initiator of coagulation, may have additional roles, outside of fibrin formation, that are central to the biology of some solid tumors.

  10. Hemostasis and malignancy.

    PubMed

    Francis, J L; Biggerstaff, J; Amirkhosravi, A

    1998-01-01

    There is considerable evidence that the hemostatic system is involved in the growth and spread of malignant disease. There is an increased incidence of thromboembolic disease in patients with cancers and hemostatic abnormalities are extremely common in such patients. Antihemostatic agents have been successfully used to treat a variety of experimental tumors, and several clinical trials in humans have been initiated. Although metastasis is undoubtedly multifactorial, intravascular coagulation activation and peritumor fibrin deposition seem to be important. The mechanisms by which hemostatic activation facilitates the malignant process remain to be completely elucidated. Of central importance may be the presence on malignant cells of tissue factor and urokinase receptor. Recent studies have suggested that these proteins, and others, may be involved at several stages of metastasis, including the key event of neovascularization. Tissue factor, the principal initiator of coagulation, may have additional roles, outside of fibrin formation, that are central to the biology of some solid tumors. PMID:9579631

  11. Malignancy-Associated Dyslipidemia

    PubMed Central

    Bielecka-Dąbrowa, Agata; Hannam, Simon; Rysz, Jacek; Banach, Maciej

    2011-01-01

    Cholesterol and triglycerides, important lipid constituents of cell, are essential to carry out several vital physiological functions. Lipids might be associated with cancers because they play a key role in the maintenance of cell integrity. The pathway for cholesterol synthesis may also produce various tumorigenic compounds and cholesterol serves as a precursor for the synthesis of many sex hormones linked to increased risk of various cancers. In some malignant diseases, blood cholesterol undergoes early and significant changes. The mechanism for the link between cancer and cholesterol remains controversial. The dates from studies are confusing because both hypolipidemia and hypercholesterolemia might be connected with malignancy. Not only cancers but also antineoplastic therapies have an influence on lipid profile. There are also dates suggesting that antihyperlipemic drugs might nfluenced malignancy. PMID:21660223

  12. Magnitudes of selected stellar occultation candidates for Pluto and other planets, with new predictions for Mars and Jupiter

    NASA Technical Reports Server (NTRS)

    Sybert, C. B.; Bosh, A. S.; Sauter, L. M.; Elliot, J. L.; Wasserman, L. H.

    1992-01-01

    Occultation predictions for the planets Mars and Jupiter are presented along with BVRI magnitudes of 45 occultation candidates for Mars, Jupiter, Saturn, Uranus, and Pluto. Observers can use these magnitudes to plan observations of occultation events. The optical depth of the Jovian ring can be probed by a nearly central occultation on 1992 July 8. Mars occults an unusually red star in early 1993, and the occultations for Pluto involving the brightest candidates would possibly occur in the spring of 1992 and the fall of 1993.

  13. THE 1998 NOVEMBER 14 OCCULTATION OF GSC 0622-00345 BY SATURN. I. TECHNIQUES FOR GROUND-BASED STELLAR OCCULTATIONS

    SciTech Connect

    Harrington, Joseph; French, Richard G. E-mail: rfrench@wellesley.ed

    2010-06-10

    On 1998 November 14, Saturn and its rings occulted the star GSC 0622-00345. We observed atmospheric immersion with NSFCAM at the National Aeronautics and Space Administration's Infrared Telescope Facility on Mauna Kea, Hawaii. Immersion occurred at 55.{sup 0}5 S planetocentric latitude. A 2.3 {mu}m, CH{sub 4}-band filter suppressed reflected sunlight. Atmospheric emersion and ring data were not successfully obtained. We describe our observation, light curve production, and timing techniques, including improvements in aperture positioning, removal of telluric scintillation effects, and timing. Many of these techniques are known within the occultation community, but have not been described in the reviewed literature. We present a light curve whose signal-to-noise ratio per scale height is 267, among the best ground-based signals yet achieved, despite a disadvantage of up to 8 mag in the stellar flux compared to prior work.

  14. A search for stellar occultations by Uranus, Neptune, Pluto, and their satellites: 1990-1999

    NASA Technical Reports Server (NTRS)

    Mink, Douglas J.

    1991-01-01

    A search for occultations of stars by Uranus, Neptune, and Pluto between 1990 and 1999 was carried out by combining ephemeris information and star positions using very accurate occultation modeling software. Stars from both the Space Telescope Guide Catalog and photographic plates taken by Arnold Klemola at Lick Observatory were compared with planet positions from the JPL DE-130 ephemeris, with local modifications for Pluto and Charon. Some 666 possible occultations by the Uranian ring, 143 possible occultations by Neptune, and 40 possible occultations by Pluto and/or Charon were found among stars with visual magnitudes as faint as 16. Before the star positions could be obtained, the occultation prediction software was used to aid many observers in observing the occultation of 28 Sagitarii by Saturn in July 1989. As a test on other outer solar system objects, 17 possible occultations were found in a search of the Guide Star Catalog for occultations by 2060 Chiron, and interesting object between Saturn and Uranus which shows both cometary and asteroidal properties.

  15. High spatial resolution multi-color observations of Neptune during occultation by the moon

    NASA Technical Reports Server (NTRS)

    Veverka, J.

    1976-01-01

    Preparations for the observation of Mars occultation using the 36 inch telescope on a C-141 airborne observatory were described, including technical improvements made to existing equipment. The abstracts of the following four publications supported by the grant were presented: (1) atmosphere composition from refractivity measurements made during occultations, (2) how big is lapetus?, (3) the diameter of Titan, (4) design and operating characteristics of voltage to frequency converters suited for occultation work. The planned observation of the April 8, 1976 occultation of the epsilon Gem star from the C-141 airborne observatory was described.

  16. Medial Biceps Sling Takedown May Be Necessary to Expose an Occult Subscapularis Tendon Tear

    PubMed Central

    Hartzler, Robert U.; Burkhart, Stephen S.

    2014-01-01

    With a systematic approach to diagnosis, including a thorough history, physical examination, advanced imaging, and arthroscopic evaluation, most subscapularis tendon tears may be readily discovered. Occult tears, on the other hand, may escape arthroscopic detection if a high index of suspicion and certain intraoperative examination steps are lacking. We describe an occult tear pattern in which a subscapularis tendon tear was completely hidden by an intact medial biceps tendon sling. Takedown of the sling, which was expendable because a tenodesis was planned, was required to expose this occult tear. Awareness of occult subscapularis tear patterns makes diagnosis and repair possible. PMID:25685681

  17. Probing the Martian Atmosphere with MAVEN/IUVS Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Gröller, H.; Yelle, R. V.; Koskinen, T.; Montmessin, F.; Lacombe, G.; Schneider, N. M.; Deighan, J.; Stewart, I. F.; Jain, S.; Chaffin, M.; Crismani, M. M. J.; Stiepen, A.; Lefèvre, F.; McClintock, B.; Clarke, J. T.; Holsclaw, G.; Mahaffy, P. R.; Bougher, S. W.; Jakosky, B. M.

    2015-12-01

    We present the first results of FUV and MUV stellar occultations taken with the Imaging UltraViolet Spectrometer (IUVS) onboard MAVEN. The FUV and MUV channels of the IUVS together cover the spectral range from 115 to 330 nm. The first two campaigns were executed during March 24 and March 26, 2015, and during May 17 and May 18, 2015, respectively. So far 13 occultations could be used to retrieve CO2 and O2 number densities in the altitude range between 100 and 150 km from the first occultation campaign. From the second occultation campaign number densities for CO2, O3, and aerosols were obtained between 20 and 100 km altitude. Temperature profiles for the same altitude ranges were calculated by applying the constraint of hydrostatic equilibrium to the CO2 densities. With a cadence of 2.6 s, including a 2.0 s integration time, the altitude resolution of the density and temperature profiles is between 1.5 and 4.5 km, depending on the geometry of the particular occultation. The retrieved density profiles of CO2 and O2 agree with previous measurements obtained by the Mars Express SPICAM instrument and by Viking 1 and 2. The corresponding O2 mixing ratios range from 1 to 5 x 10-3, also in agreement with previous observations. The temperatures that we retrieved agree with the models in the Mars Climate Database (MCD) between 10-2 and 10-4 Pa. At lower pressures, however, the measured temperatures are on average 70 K to 100 K cooler than the temperatures predicted by the MCD. This is because the model temperatures increase steadily with altitude above the mesopause whereas the observed temperatures decrease at pressures less than 3.5 x 10-5 Pa, reaching a minimum near 7 x 10-6 Pa. The large differences between the MCD and our results indicate that global models of thermal structure around the mesopause need to be revised.

  18. Association between high-sensitivity C-reactive protein (hsCRP) and change in mammographic density over time in the SWAN mammographic density subcohort

    PubMed Central

    Gold, Ellen B.; Harvey, Danielle J.; Butler, Lesley M.; Habel, Laurel A.

    2015-01-01

    Purpose High mammographic density (MD) is a strong risk factor for breast cancer. Chronic inflammation may be related to breast cancer risk through a mechanism involving the percent of breast area that is dense (percent MD). Longitudinal assessments, however, are lacking and thus were constructed to evaluate the relationship between chronic inflammation and percent MD. Methods We evaluated whether elevated (>3 mg/L) high-sensitivity C-reactive protein (hsCRP), a biomarker of inflammation, was associated with change in percent MD among 653 women aged 42–52 years at baseline in the Study of Women’s Health Across the Nation, a longitudinal study of midlife women. We used a mixed model to analyze data from an average of 4.7 mammograms per woman collected during an average follow-up of 4.9 years (SD = 1.47). Results Elevated hsCRP at baseline was associated with lower baseline percent MD and a significantly slower annual decline over time of percent MD in an adjusted model that did not include body mass index (BMI) (β = 0.88, 95 % CI 0.44, 1.31). This association was attenuated and nonsignificant when BMI was included in the model (β = 0.37, 95 % CI −0.09, 0.84). Elevated hsCRP levels over time (time-varying elevated hsCRP levels) were also associated with a significantly slower decline in percent MD (β = 0.62, 95 % CI 0.30, 0.94). This association was attenuated, but still significant after adjusting for baseline BMI (β = 0.40, 95 % CI 0.07, 0.73). Conclusion These results suggest that inflammation may be related to slower reduction in percent MD. PMID:25604866

  19. Profiling the atmosphere with the airborne radio occultation technique

    NASA Astrophysics Data System (ADS)

    Muradyan, Paytsar

    The GNSS Instrument System for Multistatic and Occultation Sensing (GISMOS) was designed for dense sampling of meteorological targets using the airborne radio occultation (RO) technique. Airborne RO refers to an atmospheric limb sounding technique in which Global Positioning System (GPS) signals are recorded at a receiver onboard an aircraft as the satellites descend beyond the limb of the Earth. The GPS signals, that are unaffected by clouds and precipitation, experience refractive bending as well as a delay in the travel time through the atmosphere. Bending can be used to retrieve information about atmospheric refractivity, which depends on atmospheric moisture and temperature. The new system has the potential for improving numerical weather prediction (NWP) forecasts through assimilation of many high-resolution atmospheric profiles in an area of interest, compared to spaceborne RO, which samples sparsely around the globe. In February 2008, GISMOS was deployed on the National Science Foundation Gulfstream-V aircraft to make atmospheric observations in the Gulf of Mexico coastal region with an objective to test the performance of the profiling system. Recordings from this flight campaign made with the conventional phase lock loop GPS receivers descend from flight level to 5 km altitude. However, below that level strong refractivity gradients, especially those associated with the boundary layer, cause rapid phase accelerations resulting in loss of lock in the receiver. To extend the RO profiles deeper in the atmosphere, the GISMOS system was also equipped with a GPS Recording System (GRS) that records the raw RF signals. Post-processing this dataset in open-loop (OL) tracking mode enables reliable atmospheric profiling at lower altitudes. We present a comprehensive analysis of the performance of the airborne system OL tracking algorithm during a 5 hour flight on 15 February 2008. Excess phase and amplitude profiles for 5 setting and 5 rising occultations were

  20. A comparative study of chemical and immunological method of fecal occult blood test in the diagnosis of occult lower gastrointestinal bleeding.

    PubMed

    Yeasmin, F; Ali, M A; Rahman, M A; Sultana, T; Rahman, M Q; Ahmed, A N N

    2013-08-01

    Fecal occult blood test is the most widely used screening test for diagnosis of gastrointestinal bleeding disorders specially colorectal carcinoma. Among the various methods of fecal occult blood tests, chemical method is being used commonly, but the method has some drawbacks like low participation rate, high false positive rate, low sensitivity etc. To overcome these short comings, newer immunological method was introduced. This study evaluated the role of immunological method of fecal blood test in the diagnosis of occult lower GIT bleeding. Stool samples from two hundred patients were examined by both chemical and immunological method. The patients who were positive by any or both methods of occult blood test, were advised for colonoscopy. During colonoscopy tissues were taken for histopathology which was the gold standard of this study. Among 110 OBT positive patients pathological lesions were detected in 65 patients by colonoscopy and histopathology. The diseases detected by colonoscopy and histopathology 18 colorectal polyp, 8 colorectal cancer, 24 ulcerative lesions and 5 inflammatory bowel disease etc. Regarding comparative analysis of chemical and immunological method, the higher sensitivity (95.4% vs. 49.2%), specificity (44.4% vs. 37.8%), accuracy (74.5% vs. 44.5%), PPV (71.3% vs. 53.3%) and NPV (87% vs. 34%) of immunological method than chemical method was observed. Thus immunological method of fecal occult blood test was appeared to be a better alternative to conventional chemical method of fecal occult blood test in the diagnosis of occult lower GIT bleeding.

  1. "Malignant Cutaneous Ulcer".

    PubMed

    Sundriyal, Deepak; Kotwal, Sumedha

    2016-09-01

    Renal cell carcinoma (RCC) is an aggressive malignancy and the rich vascular supply enables it to metastasize early via haematogenous route. Skin lesions are a late manifestation of the disease. Clinicians should be aware of cutaneous presentation of RCC while evaluating a case of unknown primary with skin lesions. PMID:27651705

  2. Immunotherapy for malignant glioma.

    PubMed

    Suryadevara, Carter M; Verla, Terence; Sanchez-Perez, Luis; Reap, Elizabeth A; Choi, Bryan D; Fecci, Peter E; Sampson, John H

    2015-01-01

    Malignant gliomas (MG) are the most common type of primary malignant brain tumor. Most patients diagnosed with glioblastoma (GBM), the most common and malignant glial tumor, die within 12-15 months. Moreover, conventional treatment, which includes surgery followed by radiation and chemotherapy, can be highly toxic by causing nonspecific damage to healthy brain and other tissues. The shortcomings of standard-of-care have thus created a stimulus for the development of novel therapies that can target central nervous system (CNS)-based tumors specifically and efficiently, while minimizing off-target collateral damage to normal brain. Immunotherapy represents an investigational avenue with the promise of meeting this need, already having demonstrated its potential against B-cell malignancy and solid tumors in clinical trials. T-cell engineering with tumor-specific chimeric antigen receptors (CARs) is one proven approach that aims to redirect autologous patient T-cells to sites of tumor. This platform has evolved dramatically over the past two decades to include an improved construct design, and these modern CARs have only recently been translated into the clinic for brain tumors. We review here emerging immunotherapeutic platforms for the treatment of MG, focusing on the development and application of a CAR-based strategy against GBM.

  3. Mammographic parenchymal texture as an imaging marker of hormonal activity: a comparative study between pre- and post-menopausal women

    NASA Astrophysics Data System (ADS)

    Daye, Dania; Bobo, Ezra; Baumann, Bethany; Ioannou, Antonios; Conant, Emily F.; Maidment, Andrew D. A.; Kontos, Despina

    2011-03-01

    Mammographic parenchymal texture patterns have been shown to be related to breast cancer risk. Yet, little is known about the biological basis underlying this association. Here, we investigate the potential of mammographic parenchymal texture patterns as an inherent phenotypic imaging marker of endogenous hormonal exposure of the breast tissue. Digital mammographic (DM) images in the cranio-caudal (CC) view of the unaffected breast from 138 women diagnosed with unilateral breast cancer were retrospectively analyzed. Menopause status was used as a surrogate marker of endogenous hormonal activity. Retroareolar 2.5cm2 ROIs were segmented from the post-processed DM images using an automated algorithm. Parenchymal texture features of skewness, coarseness, contrast, energy, homogeneity, grey-level spatial correlation, and fractal dimension were computed. Receiver operating characteristic (ROC) curve analysis was performed to evaluate feature classification performance in distinguishing between 72 pre- and 66 post-menopausal women. Logistic regression was performed to assess the independent effect of each texture feature in predicting menopause status. ROC analysis showed that texture features have inherent capacity to distinguish between pre- and post-menopausal statuses (AUC>0.5, p<0.05). Logistic regression including all texture features yielded an ROC curve with an AUC of 0.76. Addition of age at menarche, ethnicity, contraception use and hormonal replacement therapy (HRT) use lead to a modest model improvement (AUC=0.78) while texture features maintained significant contribution (p<0.05). The observed differences in parenchymal texture features between pre- and post- menopausal women suggest that mammographic texture can potentially serve as a surrogate imaging marker of endogenous hormonal activity.

  4. Digital versus screen-film mammography: impact of mammographic density and hormone therapy on breast cancer detection.

    PubMed

    Chiarelli, Anna M; Prummel, Maegan V; Muradali, Derek; Shumak, Rene S; Majpruz, Vicky; Brown, Patrick; Jiang, Hedy; Done, Susan J; Yaffe, Martin J

    2015-11-01

    Most studies that have examined the effects of mammographic density and hormone therapy use on breast cancer detection have included screen-film mammography. This study further examines this association in post-menopausal women screened by digital mammography. Approved by the University of Toronto Research Ethics Board, this study identified 688,418 women of age 50-74 years screened with digital or screen-film mammography from 2008 to 2009 within the Ontario Breast Screening Program. Of 2993 eligible women with invasive breast cancer, 2450 were contacted and 1421 participated (847 screen-film mammography, 574 digital direct radiography). Mammographic density was measured by study radiologists using the standard BI-RADS classification system and by a computer-assisted method. Information on hormone therapy use was collected by a telephone-administered questionnaire. Logistic regression and two-tailed tests for significance evaluated associations between factors and detection method by mammography type. Women with >75 % radiologist-measured mammographic density compared to those with <25 % were more likely to be diagnosed with an interval than screen-detected cancer, with the difference being greater for those screened with screen-film (OR = 6.40, 95 % CI 2.30-17.85) than digital mammography (OR = 2.41, 95 % CI 0.67-8.58) and aged 50-64 years screened with screen-film mammography (OR = 10.86, 95 % CI 2.96-39.57). Recent former hormone therapy users were also at an increased risk of having an interval cancer with the association being significant for women screened with digital mammography (OR = 2.08, 95 % CI 1.17-3.71). Breast screening using digital mammography lowers the risk of having an interval cancer for post-menopausal women aged 50-64 with greater mammographic density. PMID:26518019

  5. Digital versus screen-film mammography: impact of mammographic density and hormone therapy on breast cancer detection.

    PubMed

    Chiarelli, Anna M; Prummel, Maegan V; Muradali, Derek; Shumak, Rene S; Majpruz, Vicky; Brown, Patrick; Jiang, Hedy; Done, Susan J; Yaffe, Martin J

    2015-11-01

    Most studies that have examined the effects of mammographic density and hormone therapy use on breast cancer detection have included screen-film mammography. This study further examines this association in post-menopausal women screened by digital mammography. Approved by the University of Toronto Research Ethics Board, this study identified 688,418 women of age 50-74 years screened with digital or screen-film mammography from 2008 to 2009 within the Ontario Breast Screening Program. Of 2993 eligible women with invasive breast cancer, 2450 were contacted and 1421 participated (847 screen-film mammography, 574 digital direct radiography). Mammographic density was measured by study radiologists using the standard BI-RADS classification system and by a computer-assisted method. Information on hormone therapy use was collected by a telephone-administered questionnaire. Logistic regression and two-tailed tests for significance evaluated associations between factors and detection method by mammography type. Women with >75 % radiologist-measured mammographic density compared to those with <25 % were more likely to be diagnosed with an interval than screen-detected cancer, with the difference being greater for those screened with screen-film (OR = 6.40, 95 % CI 2.30-17.85) than digital mammography (OR = 2.41, 95 % CI 0.67-8.58) and aged 50-64 years screened with screen-film mammography (OR = 10.86, 95 % CI 2.96-39.57). Recent former hormone therapy users were also at an increased risk of having an interval cancer with the association being significant for women screened with digital mammography (OR = 2.08, 95 % CI 1.17-3.71). Breast screening using digital mammography lowers the risk of having an interval cancer for post-menopausal women aged 50-64 with greater mammographic density.

  6. A follow-up analysis of positron emission tomography/computed tomography in detecting hidden malignancies at the time of diagnosis of membranous nephropathy

    PubMed Central

    Feng, Zhonglin; Wang, Shuxia; Huang, Yanlin; Liang, Xinling; Shi, Wei; Zhang, Bin

    2016-01-01

    Membranous nephropathy (MN) is the most common kidney disease reported in a variety of malignant diseases. Search for an occult malignancy in MN has presented special challenges. 124 MN patients with a physical examination not suspicious for cancer underwent screening for an occult malignancy with either 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scanning (n = 49) or conventional screening (n = 75) at the time of diagnosis of MN, and were followed up (median,28 months). 154 patients who refused to undergo any screening were followed up (median, 30 months). In FDG-PET/CT cohort, 5 (10.20%) patients were screened and confirmed as malignancy, in contrast, 1 (1.33%) patient in conventional screening cohort. During follow-up, none of malignancy was detected in FDG-PET/CT cohort, 3(4.05%) patients in conventional screening cohort, and 8(5.19%) patients in no-screening cohort. All 6 cases of cancer were detected at early stages and underwent curative resection, and after the resection, proteinuria decreased. In contrast, 11 cases of cancer detected during follow-up died without any remission of proteinuria. These preliminary data provide the first evidence for a potential cancer surveillance that the malignancy screening either through conventional or by PET-CT at the diagnosis of MN led to an early diagnosis and curative treatment. PMID:27009881

  7. The psychological impact of mammographic screening on women with a family history of breast cancer--a systematic review.

    PubMed

    Watson, Eila K; Henderson, Bethan J; Brett, Joanne; Bankhead, Clare; Austoker, Joan

    2005-11-01

    This systematic review aims to assess the psychological impact of mammographic screening on women with a family history of breast cancer. Women with a family history, and hence increased risk, of breast cancer are known to experience higher levels of anxiety about cancer. They are also often offered screening from an earlier age. The psychological consequences of screening are therefore of particular importance for this group of women. A comprehensive search of 4 electronic databases was conducted from 1982 to 2003, combining sets of terms relating to (1) breast screening or mammography (breast screen*; mammogra*), (2) psychological impact (adverse effects; anxi*; distress; nervous; psych*, psychological consequences; stress; worry) and (3) family history. Reference lists from relevant papers were examined for additional papers. The review identified seven papers from four countries. Overall, the findings indicate that, similar to women in the general population, most women with a family history do not appear to experience high levels of anxiety associated with mammographic screening. Although women who are recalled for further tests do experience increased anxiety the levels appear to be no greater than for women without a family history. We conclude that further research on this topic is required--this should include studies designed specifically to consider both the negative and positive impact of mammographic screening on women with a family history, using validated measures of anxiety and worry in combination with qualitative research.

  8. Genome-wide association study identifies multiple loci associated with both mammographic density and breast cancer risk

    PubMed Central

    Lindström, Sara; Thompson, Deborah J.; Paterson, Andrew D.; Li, Jingmei; Gierach, Gretchen L.; Scott, Christopher; Stone, Jennifer; Douglas, Julie A.; dos-Santos-Silva, Isabel; Fernandez-Navarro, Pablo; Verghase, Jajini; Smith, Paula; Brown, Judith; Luben, Robert; Wareham, Nicholas J.; Loos, Ruth J.F.; Heit, John A.; Pankratz, V. Shane; Norman, Aaron; Goode, Ellen L.; Cunningham, Julie M.; deAndrade, Mariza; Vierkant, Robert A.; Czene, Kamila; Fasching, Peter A.; Baglietto, Laura; Southey, Melissa C.; Giles, Graham G.; Shah, Kaanan P.; Chan, Heang-Ping; Helvie, Mark A.; Beck, Andrew H.; Knoblauch, Nicholas W.; Hazra, Aditi; Hunter, David J.; Kraft, Peter; Pollan, Marina; Figueroa, Jonine D.; Couch, Fergus J.; Hopper, John L.; Hall, Per; Easton, Douglas F.; Boyd, Norman F.; Vachon, Celine M.; Tamimi, Rulla M.

    2015-01-01

    Mammographic density reflects the amount of stromal and epithelial tissues in relation to adipose tissue in the breast and is a strong risk factor for breast cancer. Here we report the results from meta-analysis of genome-wide association studies (GWAS) of three mammographic density phenotypes: dense area, non-dense area and percent density in up to 7,916 women in stage 1 and an additional 10,379 women in stage 2. We identify genome-wide significant (P<5×10−8) loci for dense area (AREG, ESR1, ZNF365, LSP1/TNNT3, IGF1, TMEM184B, SGSM3/MKL1), non-dense area (8p11.23) and percent density (PRDM6, 8p11.23, TMEM184B). Four of these regions are known breast cancer susceptibility loci, and four additional regions were found to be associated with breast cancer (P<0.05) in a large meta-analysis. These results provide further evidence of a shared genetic basis between mammographic density and breast cancer and illustrate the power of studying intermediate quantitative phenotypes to identify putative disease susceptibility loci. PMID:25342443

  9. Predicted image quality of a CMOS APS X-ray detector across a range of mammographic beam qualities

    NASA Astrophysics Data System (ADS)

    Konstantinidis, A.

    2015-09-01

    Digital X-ray detectors based on Complementary Metal-Oxide- Semiconductor (CMOS) Active Pixel Sensor (APS) technology have been introduced in the early 2000s in medical imaging applications. In a previous study the X-ray performance (i.e. presampling Modulation Transfer Function (pMTF), Normalized Noise Power Spectrum (NNPS), Signal-to-Noise Ratio (SNR) and Detective Quantum Efficiency (DQE)) of the Dexela 2923MAM CMOS APS X-ray detector was evaluated within the mammographic energy range using monochromatic synchrotron radiation (i.e. 17-35 keV). In this study image simulation was used to predict how the mammographic beam quality affects image quality. In particular, the experimentally measured monochromatic pMTF, NNPS and SNR parameters were combined with various mammographic spectral shapes (i.e. Molybdenum/Molybdenum (Mo/Mo), Rhodium/Rhodium (Rh/Rh), Tungsten/Aluminium (W/Al) and Tungsten/Rhodium (W/Rh) anode/filtration combinations at 28 kV). The image quality was measured in terms of Contrast-to-Noise Ratio (CNR) using a synthetic breast phantom (4 cm thick with 50% glandularity). The results can be used to optimize the imaging conditions in order to minimize patient's Mean Glandular Dose (MGD).

  10. Genome-wide association study identifies multiple loci associated with both mammographic density and breast cancer risk.

    PubMed

    Lindström, Sara; Thompson, Deborah J; Paterson, Andrew D; Li, Jingmei; Gierach, Gretchen L; Scott, Christopher; Stone, Jennifer; Douglas, Julie A; dos-Santos-Silva, Isabel; Fernandez-Navarro, Pablo; Verghase, Jajini; Smith, Paula; Brown, Judith; Luben, Robert; Wareham, Nicholas J; Loos, Ruth J F; Heit, John A; Pankratz, V Shane; Norman, Aaron; Goode, Ellen L; Cunningham, Julie M; deAndrade, Mariza; Vierkant, Robert A; Czene, Kamila; Fasching, Peter A; Baglietto, Laura; Southey, Melissa C; Giles, Graham G; Shah, Kaanan P; Chan, Heang-Ping; Helvie, Mark A; Beck, Andrew H; Knoblauch, Nicholas W; Hazra, Aditi; Hunter, David J; Kraft, Peter; Pollan, Marina; Figueroa, Jonine D; Couch, Fergus J; Hopper, John L; Hall, Per; Easton, Douglas F; Boyd, Norman F; Vachon, Celine M; Tamimi, Rulla M

    2014-01-01

    Mammographic density reflects the amount of stromal and epithelial tissues in relation to adipose tissue in the breast and is a strong risk factor for breast cancer. Here we report the results from meta-analysis of genome-wide association studies (GWAS) of three mammographic density phenotypes: dense area, non-dense area and percent density in up to 7,916 women in stage 1 and an additional 10,379 women in stage 2. We identify genome-wide significant (P<5 × 10(-8)) loci for dense area (AREG, ESR1, ZNF365, LSP1/TNNT3, IGF1, TMEM184B and SGSM3/MKL1), non-dense area (8p11.23) and percent density (PRDM6, 8p11.23 and TMEM184B). Four of these regions are known breast cancer susceptibility loci, and four additional regions were found to be associated with breast cancer (P<0.05) in a large meta-analysis. These results provide further evidence of a shared genetic basis between mammographic density and breast cancer and illustrate the power of studying intermediate quantitative phenotypes to identify putative disease-susceptibility loci. PMID:25342443

  11. Mutations Associated With Occult Hepatitis B in HIV-Positive South Africans

    PubMed Central

    Powell, Eleanor A.; Gededzha, Maemu P.; Rentz, Michael; Rakgole, Nare J.; Selabe, Selokela G.; Seleise, Tebogo A.; Mphahlele, M. Jeffrey; Blackard, Jason T.

    2015-01-01

    Occult hepatitis B is characterized by the absence of hepatitis B surface antigen (HBsAg) but the presence of HBV DNA. Because diagnosis of hepatitis B virus (HBV) typically includes HBsAg detection, occult HBV remains largely undiagnosed. Occult HBV is associated with increased risk of hepatocellular carcinoma, reactivation to chronic HBV during immune suppression, and transmission during blood transfusion and liver transplant. The mechanisms leading to occult HBV infection are unclear, although viral mutations are likely a significant factor. In this study, sera from 394 HIV-positive South Africans were tested for HBV DNA and HBsAg. For patients with detectable HBV DNA, the overlapping surface and polymerase open reading frames (ORFs) were sequenced. Occult-associated mutations—those mutations found exclusively in individuals with occult HBV infection but not in individuals with chronic HBV infection from the same cohort or GenBank references—were identified. Ninety patients (22.8%) had detectable HBV DNA. Of these, 37 had detectable HBsAg, while 53 lacked detectable surface antigen. The surface and polymerase ORFs were cloned successfully for 19 patients with chronic HBV and 30 patients with occult HBV. In total, 235 occult-associated mutations were identified. Ten occult-associated mutations were identified in more than one patient. Additionally, 15 amino acid positions had two distinct occult-associated mutations at the same residue. Occult-associated mutations were common and present in all regions of the surface and polymerase ORFs. Further study is underway to determine the effects of these mutations on viral replication and surface antigen expression in vitro. PMID:25164924

  12. Mutations associated with occult hepatitis B in HIV-positive South Africans.

    PubMed

    Powell, Eleanor A; Gededzha, Maemu P; Rentz, Michael; Rakgole, Nare J; Selabe, Selokela G; Seleise, Tebogo A; Mphahlele, M Jeffrey; Blackard, Jason T

    2015-03-01

    Occult hepatitis B is characterized by the absence of hepatitis B surface antigen (HBsAg) but the presence of HBV DNA. Because diagnosis of hepatitis B virus (HBV) typically includes HBsAg detection, occult HBV remains largely undiagnosed. Occult HBV is associated with increased risk of hepatocellular carcinoma, reactivation to chronic HBV during immune suppression, and transmission during blood transfusion and liver transplant. The mechanisms leading to occult HBV infection are unclear, although viral mutations are likely a significant factor. In this study, sera from 394 HIV-positive South Africans were tested for HBV DNA and HBsAg. For patients with detectable HBV DNA, the overlapping surface and polymerase open reading frames (ORFs) were sequenced. Occult-associated mutations-those mutations found exclusively in individuals with occult HBV infection but not in individuals with chronic HBV infection from the same cohort or GenBank references-were identified. Ninety patients (22.8%) had detectable HBV DNA. Of these, 37 had detectable HBsAg, while 53 lacked detectable surface antigen. The surface and polymerase ORFs were cloned successfully for 19 patients with chronic HBV and 30 patients with occult HBV. In total, 235 occult-associated mutations were identified. Ten occult-associated mutations were identified in more than one patient. Additionally, 15 amino acid positions had two distinct occult-associated mutations at the same residue. Occult-associated mutations were common and present in all regions of the surface and polymerase ORFs. Further study is underway to determine the effects of these mutations on viral replication and surface antigen expression in vitro.

  13. Malignant Melanoma of the Foot

    MedlinePlus

    ... Javascript in your browser. Malignant Melanoma of the Foot What is Malignant Melanoma? Melanoma is a cancer ... age groups, even the young. Melanoma in the Foot Melanoma that occurs in the foot or ankle ...

  14. Clinical evaluation of cytological diagnosis of nasopharyngeal malignancies.

    PubMed

    Molinari, R; Pilotti, S; Rilke, F

    1978-01-01

    Between 1970 and 1975 cytological examination was applied to the diagnosis of nasopharyngeal malignancies in a series of 216 consecutive patients who had either a tumour in the nasopharynx or clinical signs of nasopharyngeal carcinoma, or who were locally asymptomatic but had enlarged cervical lymph nodes. Smears were taken by introducing a small rough pad of compressed gauze through the mouth into the nasopharynx with an upward-angled forceps. In each case the cytological smear was taken immediately before biopsy; often, a lymph node was removed subsequently. When morphological diagnoses were doubtful and histological findings were at variance with positive cytological findings, the patients were reexamined clinically, and diagnosis was postponed. The case material was made up of 90 nasopharyngeal carcinomas, 24 lymphomas, one malignant melanoma, one adenoid cystic carcinoma and 100 patients without malignancies. Cytological findings from the first smear were positive in 77.8% of nasopharyngeal carcinomas, in 66.6% of lymphomas and in the cases of melanoma and adenoid cystic carcinoma. There were no false-positive results. When the nasopharyngeal carcinomas were subdivided into undifferentiated carcinomas of the nasopharyngeal type and squamous-cell carcinomas, cytological findings were positive in ,0% and 73%, respectively. Positivity of histological findings was distributed as follows: 91.7% for malignant lymphomas, 86.6% for undifferentiated carcinomas and 86.6% for squamous-cell carcinomas. With respect to clinical suspicion of malignancy, positive cytological findings were obtained in 50% of clinically occult cases and in 84.6% of patients with obvious malignancies; intermediate figures were found for clinically doubtful (64.3%) and for highly suspicious (77.8%) cases. Cyto-histological concordance was shown in 70% of cases; false-negative histological results were obtained in 7.8% and false-negative cytological results in 16.6% of cases. Combined cyto

  15. [Investigation of occult hepatitis B in HIV infected patients].

    PubMed

    Altınbaş, Akif; Ergünay, Koray; Calık Başaran, Nursel; Alp, Alpaslan; Turgut, Didem; Hasçelik, Gülşen; Uzun, Ömrüm; Unal, Serhat

    2011-04-01

    Due to their shared transmission route, hepatitis B virus (HBV) or hepatitis C virus (HCV) co-infections can be observed in human immunodeficiency virus (HIV)-infected cases and are associated with more severe clinical courses. The detection of HBV DNA despite HBV surface antigen (HBsAg) seronegativity is defined as occult HBV infections. According to the current seroepidemiological data, Turkey is classified as an intermediate HBV, low HIV endemic region. Occult HBV infections have previously been reported from Turkey but has not been investigated previously in HIV infected cohorts. The aim of this study was to identify occult HBV infections in HIV-infected persons. Twenty-eight HIV-positive cases followed-up at Hacettepe University Hospital, Infectious Diseases Unit were included in the study after informed consent. For the detection of HBsAg, anti-HBs and anti-HCV, commercial ELISA tests (Architect System, Abbott Diagnostics, USA) were employed. Absolute CD4+ and CD8+ T-cell counts were determined via flow cytometry. HIV viral load was calculated via COBAS TaqMan HIV-1 Real-time PCR (Roche Diagnostics, USA) and the presence of HBV DNA was evaluated via COBAS TaqMan HBV Real-time PCR (Roche Diagnostics, USA), in addition to a nested PCR assay targeting HBV S gene. The mean age of the study group was 43.2 (range between 27-65) years, 64.3% (18/28) of them were males and the mean duration of HIV infection was 4.2 (2-11) years. Mean CD4+ ve CD8+ T-cell counts were 414 ± 267 cells/mm3 and 854 ± 293 cells/mm3, respectively. Twenty-six (92.8%) cases were under highly-active anti-retroviral therapy at the time of the study, 88.5% of which included HBV-active drugs (lamivudine or tenofovir). HIV RNA were found negative in 11 (39.3%) patients, of those nine (81.8%) were the cases who treated with HBV-active antiretroviral therapy. HBsAg were negative in all of the 28 patients, while the positivity rates of anti-HBs and anti-HCV were 39.3% (11/28) and 3.6% (1

  16. Diffraction-based sensitivity analysis for an external occulter laboratory demonstration.

    PubMed

    Sirbu, Dan; Kim, Yunjong; Jeremy Kasdin, N; Vanderbei, Robert J

    2016-08-01

    An external flower-shaped occulter flying in formation with a space telescope can theoretically provide sufficient starlight suppression to enable direct imaging of an Earth-like planet. Occulter shapes are scaled to enable experimental validation of their performance at laboratory dimensions. Previous experimental results have shown promising performance but have not realized the full theoretical potential of occulter designs. Here, we develop a two-dimensional diffraction model for optical propagations for occulters incorporating experimental errors. We perform a sensitivity analysis, and comparison with experimental results from a scaled-occulter testbed validates the optical model to the 10-10 contrast level. The manufacturing accuracy along the edge of the occulter shape is identified as the limiting factor to achieving the theoretical potential of the occulter design. This hypothesis is experimentally validated using a second occulter mask manufactured with increased edge feature accuracy and resulting in a measured contrast level approaching the 10-12 level-a better than one order of magnitude improvement in performance. PMID:27505392

  17. The diameter of 88 Thisbe from its occultation of SAO 187124

    NASA Technical Reports Server (NTRS)

    Millis, R. L.; Wasserman, L. H.; Franz, O. G.; White, N. M.; Bowell, E.; Klemola, A.; Elliott, R. C.; Smethells, W. G.; Price, P. M.; Mckay, C. P.

    1982-01-01

    The 7 October, 1981 occultation of SAO 187124 by 88 Thisbe was observed at twelve sites. The occultation observations, together with information about the asteroid's light curve, gives a mean diameter for Thisbe of 232 + or - 10 km. This value is 10 percent larger than the previously published radiometric diameter of Thisbe.

  18. External occulter edge scattering control using metamaterials for exoplanet detection

    NASA Astrophysics Data System (ADS)

    Bendek, Eduardo A.; Sirbu, Dan; Liu, Zhaowei; Martin, Stefan; Lu, Dylan

    2015-09-01

    Direct imaging of earth-like exoplanets in the Habitable Zone of sun-like stars requires image contrast of ~10^10 at angular separations of around a hundred milliarcseconds. One approach for achieving this performance is to fly a starshade at a long distance in front of the telescope, shading the telescope from the direct starlight, but allowing planets around the star to be seen. The starshade is positioned so that sunlight falls on the surface away from the telescope, so the sun does not directly illuminate it. However, sunlight scattered from the starshade edge can enter the telescope, raising the background light level and potentially preventing the starshade from delivering the required contrast. As a result, starshade edge design has been identified as one of the highest priority technology gaps for external occulter missions in the NASAs Exoplanet Exploration Program Technology Plan 2013. To reduce the sunlight edge scatter to an acceptable level, the edge Radius Of Curvature (ROC) should be 1μm or less (commercial razor blades have ROC of a few hundred nanometer). This poses a challenging manufacturing requirement and may make the occulter difficult to handle. In this paper we propose an alternative approach to controlling the edge scattering by applying a flexible metamaterial to the occulter edge. Metamaterials are artificially structured materials, which have been designed to display properties not found in natural materials. Metamaterials can be designed to direct the scatter at planned incident angles away from the space telescope, thereby directly decreasing the contaminating background light. Reduction of the background light translates into shorter integration time to characterize a target planet and therefore improves the efficiency of the observations. As an additional benefit, metamaterials also have potential to produce increased tolerance to edge defects.

  19. Fabrication of Soft-Edged Occulting Masks for Coronagraphs

    NASA Astrophysics Data System (ADS)

    Tolls, Volker; Aziz, M. J.; Raja, S.

    2009-01-01

    Direct imaging of extra-solar planets is important for determining the properties of individual planets and to study multi-planet systems. Obtaining spectra of extra-solar planets enables us to constrain the composition of planetary atmospheres and surfaces, their climates, their evolution, and their rotation periods. The Lyot coronagraph is one of the important techniques to acquire these spectra. In its simplest design it consists of a telescope, an occulter mask in the first focal plane, a Lyot stop in the following pupil plane, and the detector in the final focal plane. The goal of ongoing research is to achieve the best possible performance from a Lyot coronagraph. Among the study objects is the occulter mask. We are studying a new manufacturing method to overcome the main problems of occulter masks: undesired chromatic effects and intolerable phase distortions. Our method utilizes substrates covered with highly absorbing dye mixtures (optical density of 1 per micron) and focused ion beam (FIB) milling of the mask profiles into these dyes. By combining several dyes with pre-determined mixing ratios, we are able to control the chromaticity of the mask from decreasing to flat to increasing absorptivity with wavelengths. Phase effects occur in these masks only at the transition from the dye to its surrounding medium. The idea is to control these phase effects by embedding the masks in clear, phase-matching glass. This poster will present the progress we made in finding and characterizing suitable materials and the results of first optical tests of FIB machined mask-like structures in dye-doped PMMA. This work was supported by NASA through grant NNG04GC57G and NSF through grant AST-0750222, through SAO IR&D funding and by Harvard University. Central facilities were provided by Harvard's Center for Nanoscale Systems.

  20. Radio Occultation Investigation of the Rings of Saturn and Uranus

    NASA Technical Reports Server (NTRS)

    Marouf, Essam A.

    1997-01-01

    The proposed work addresses two main objectives: (1) to pursue the development of the random diffraction screen model for analytical/computational characterization of the extinction and near-forward scattering by ring models that include particle crowding, uniform clustering, and clustering along preferred orientations (anisotropy). The characterization is crucial for proper interpretation of past (Voyager) and future (Cassini) ring, occultation observations in terms of physical ring properties, and is needed to address outstanding puzzles in the interpretation of the Voyager radio occultation data sets; (2) to continue the development of spectral analysis techniques to identify and characterize the power scattered by all features of Saturn's rings that can be resolved in the Voyager radio occultation observations, and to use the results to constrain the maximum particle size and its abundance. Characterization of the variability of surface mass density among the main ring, features and within individual features is important for constraining the ring mass and is relevant to investigations of ring dynamics and origin. We completed the developed of the stochastic geometry (random screen) model for the interaction of electromagnetic waves with of planetary ring models; used the model to relate the oblique optical depth and the angular spectrum of the near forward scattered signal to statistical averages of the stochastic geometry of the randomly blocked area. WE developed analytical results based on the assumption of Poisson statistics for particle positions, and investigated the dependence of the oblique optical depth and angular spectrum on the fractional area blocked, vertical ring profile, and incidence angle when the volume fraction is small. Demonstrated agreement with the classical radiative transfer predictions for oblique incidence. Also developed simulation procedures to generate statistical realizations of random screens corresponding to uniformly packed

  1. Axillary metastases from occult breast cancer. Our experience.

    PubMed

    Sanguinetti, Alessandro; Polistena, Andrea; D'Ermo, Giuseppe; Lucchini, Roberta; Triola, Roberta; Conti, Claudia; Avenia, Stefano; Cavallaro, Giuseppe; De Toma, Giorgio; Avenia, Nicola

    2014-02-28

    We report the case of a 63-year-old woman with occult breast cancer who presented with a hard metastatic nodule in the left axilla. Although histology identified a metastatic carcinoma in the lymph nodes, numerous tests failed to detect the primary tumor. Resected lymph node was positive for both estrogen and progesterone receptors, suggesting the breast as the site of the primary tumor. Left modified radical mastectomy was performed. Pathology revealed an invasive lobular carcinoma (2.5 x 2 mm in size) with extensive lymphatic involvement, which strongly expressed both vascular endothelial growth factor-C (VEGF-C) and VEGF-D.

  2. Halogen Occultation Experiment (HALOE) gas cell life test program

    NASA Technical Reports Server (NTRS)

    Sullivan, E. M.; Thompson, R. E.; Harvey, G. A.; Park, J. H.; Richardson, D. J.

    1983-01-01

    The Halogen Occultation Experiment (HALOE) will use gas filter correlation radiometry to measure the atmospheric concentration profiles of HCl, HF, NO, and CH4 from the Upper Atmosphere Research Satellite. The need to contain the gases for the gas filter measurements has resulted in the development of gas cells and the need for a life test program to demonstrate that the gas cells will perform their functions for extended periods (several years) of time. This report describes the tests in the life test program, the test apparatus used, and the analysis techniques developed. The report also presents data obtained during the first 14 months of the test program.

  3. Rosemary Hill Observatory lunar occultation summary for 1983-1984

    NASA Astrophysics Data System (ADS)

    Schneider, Glenn; Anderson, Chris

    1993-04-01

    The results from photometric observations of 21 previously unreported occultation disappearances obtained during the period from March 24, 1983 through March 12, 1984, with the University of Florida's Rosemary Hill Observatory 76-cm reflecting telescope are presented. Statistically significant determinations of stellar diameters are indicated for two stars: 32 Librae (12.2 mas) and BD + 22 deg 1032 (5.45 mas). Diameter measurements of marginal statistical significance are noted for two other stars (9 Cancri and 37 Capricorni). New duplicity determinations are reported for five stellar systems in this sample.

  4. Sporadic E Morphology from GPS-CHAMP Radio Occultation

    NASA Technical Reports Server (NTRS)

    Wu, Dong L.; Ao, Chi O.; Hajj, George A.; de la Torre Juarez, Manuel; Mannucci, Anthony J.

    2005-01-01

    The scintillations of phase and amplitude in terms of signal-to-noise ratio (SNR) of the GPS radio occultation signal are caused by thin ionization layers. These thin irregular electron density layers in the E region ionosphere are often called sporadic E (Es). For a monthly retrieval of Es morphology we use the variances of the phase and SNR fluctuations of worldwide 6000 GPS/CHAMP occultations in the E region. The Es climatology is studied globally with the SNR and phase variances in terms of monthly zonal means, seasonal maps, and diurnal and long-term variations. The zonal mean variances reveal strong, extended Es activities at summertime midlatitudes but weak, confined activities in wintertime high latitudes, peaking at 105 km. Global maps at 105-km altitude show clear dependence of Es activities on the geomagnetic dip angle, where the summertime midlatitude Es occurs mostly at dip angles of 30 deg. - 60 deg. and the wintertime high-latitude enhancement occurs mostly at dip angles greater than 80 deg. The midlatitude Es variances exhibit a strong semidiurnal variation with peak hours near 0800 1000 and 2000 local solar time, respectively. The peak hours are delayed slightly with decreasing height, suggesting influences from the semidiurnal tide. To provide more insights on the observed SNR and phase variances, we model radio wave propagation for the CHAMP observing geometry under several perturbed cases in the E region ionosphere. The model simulations indicate that the SNR variance has the maximum response to Es perturbations at vertical wavelengths of 1.2 km, whereas the phase response maximizes at 2 km (for the 1-s variance analysis). The characteristic scale depends little on the truncation time used in the SNR variance analysis, but it increases with the truncation time for the phase variances. Initial studies show that reasonable global Es morphology can be produced on a monthly and seasonal basis with the CHAMP one-antenna occultations. Better results

  5. The structure of Titan's atmosphere from Cassini radio occultations

    NASA Astrophysics Data System (ADS)

    Schinder, Paul J.; Flasar, F. Michael; Marouf, Essam A.; French, Richard G.; McGhee, Colleen A.; Kliore, Arvydas J.; Rappaport, Nicole J.; Barbinis, Elias; Fleischman, Don; Anabtawi, Aseel

    2011-10-01

    We present results from the two radio occultations of the Cassini spacecraft by Titan in 2006, which probed mid-southern latitudes. Three of the ingress and egress soundings occurred within a narrow latitude range, 31-34°S near the surface, and the fourth at 52.8°S. Temperature-altitude profiles for all four occultation soundings are presented, and compared with the results of the Voyager 1 radio occultation (Lindal, G.F., Wood, G.E., Hotz, H.B., Sweetnam, D.N., Eshleman, V.R., Tyler, G.L. [1983]. Icarus 53, 348-363), the HASI instrument on the Huygens descent probe (Fulchignoni, M. et al. [2005]. Nature 438, 785-791), and Cassini CIRS results (Flasar, F.M. et al. [2005]. Science 308, 975-978; Achterberg, R.K., Conrath, B.J., Gierasch, P.J., Flasar, F.M., Nixon, C.A. [2008b]. Icarus 194, 263-277). Sources of error in the retrieved temperature-altitude profiles are also discussed, and a major contribution is from spacecraft velocity errors in the reconstructed ephemeris. These can be reduced by using CIRS data at 300 km to make along-track adjustments of the spacecraft timing. The occultation soundings indicate that the temperatures just above the surface at 31-34°S are about 93 K, while that at 53°S is about 1 K colder. At the tropopause, the temperatures at the lower latitudes are all about 70 K, while the 53°S profile is again 1 K colder. The temperature lapse rate in the lowest 2 km for the two ingress (dawn) profiles at 31 and 33°S lie along a dry adiabat except within ˜200 m of the surface, where a small stable inversion occurs. This could be explained by turbulent mixing with low viscosity near the surface. The egress profile near 34°S shows a more complex structure in the lowest 2 km, while the egress profile at 53°S is more stable.

  6. Thermal design, analysis and testing of the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Foss, Richard A.; Smith, Dewey M.

    1987-01-01

    This paper briefly introduces the Halogen Occultation Experiment (HALOE) and describes the thermal requirements in some detail. The thermal design of the HALOE is described, together with the design process and the analytical techniques used to arrive at this design. The flight hardware has undergone environmental testing in a thermal vacuum chamber to validate the thermal design. The HALOE is a unique problem in thermal control due to its variable solar loading, its extremely sensitive optical components and the high degree of pointing accuracy required. This paper describes the flight hardware, the design process and its verification.

  7. Visualization and data sharing of COSMIC radio occultation dataset

    NASA Astrophysics Data System (ADS)

    Ho, Y.; Weber, W. J.; Chastang, J.; Murray, D.; McWhirter, J.; Integrated Data Viewer

    2010-12-01

    Visualizing the trajectory and the sounding profile of the COSMIC netCDF dataset, and its evolution through time is developed in Unidata's Integrated data Viewer (IDV). The COSMIC radio occultation data is located in a remote data server called RAMADDA, which is a content management system for earth science data. The combination of these two software packages provides a powerful visualization and analysis tools for sharing real time and archived data for research and education. In this presentation we would like to demonstrate the development and the usage of these two software packages.

  8. Designs and Materials for Better Coronagraph Occulting Masks

    NASA Technical Reports Server (NTRS)

    Balasubramanian, Kunjithapatham

    2010-01-01

    New designs, and materials appropriate for such designs, are under investigation in an effort to develop coronagraph occulting masks having broad-band spectral characteristics superior to those currently employed. These designs and materials are applicable to all coronagraphs, both ground-based and spaceborne. This effort also offers potential benefits for the development of other optical masks and filters that are required (1) for precisely tailored spatial transmission profiles, (2) to be characterized by optical-density neutrality and phase neutrality (that is, to be characterized by constant optical density and constant phase over broad wavelength ranges), and/or (3) not to exhibit optical- density-dependent phase shifts. The need for this effort arises for the following reasons: Coronagraph occulting masks are required to impose, on beams of light transmitted through them, extremely precise control of amplitude and phase according to carefully designed transmission profiles. In the original application that gave rise to this effort, the concern has been to develop broad-band occulting masks for NASA s Terrestrial Planet Finder coronagraph. Until now, experimental samples of these masks have been made from high-energy-beam-sensitive (HEBS) glass, which becomes locally dark where irradiated with a high-energy electron beam, the amount of darkening depending on the electron-beam energy and dose. Precise mask profiles have been written on HEBS glass blanks by use of electron beams, and the masks have performed satisfactorily in monochromatic light. However, the optical-density and phase profiles of the HEBS masks vary significantly with wavelength; consequently, the HEBS masks perform unsatisfactorily in broad-band light. The key properties of materials to be used in coronagraph occulting masks are their extinction coefficients, their indices of refraction, and the variations of these parameters with wavelength. The effort thus far has included theoretical

  9. The Burst and Transient Source Experiment (BATSE) Earth Occultation Catalog

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2004-01-01

    The hard X-ray sky was continuously monitored with the BATSE experiment on the Compton Gamma Ray observatory using the Earth Occultation method. Known sources were monitored twice every orbit and transients could be detected at about the approx. 50 mCrab level on a daily basis. I will summarize the results from our catalog of 179 monitored sources, highlighting observations of black holes and energy spectra for the 83 firmly detected sources and FITS files for all 179 sources. This web database can serve as a guide and comparison tool for future observations with EXIST.

  10. Hyaluronan in human malignancies

    SciTech Connect

    Sironen, R.K.; Tammi, M.; Tammi, R.; Auvinen, P.K.; Anttila, M.; Kosma, V-M.

    2011-02-15

    Hyaluronan, a major macropolysaccharide in the extracellular matrix of connective tissues, is intimately involved in the biology of cancer. Hyaluronan accumulates into the stroma of various human tumors and modulates intracellular signaling pathways, cell proliferation, motility and invasive properties of malignant cells. Experimental and clinicopathological evidence highlights the importance of hyaluronan in tumor growth and metastasis. A high stromal hyaluronan content is associated with poorly differentiated tumors and aggressive clinical behavior in human adenocarcinomas. Instead, the squamous cell carcinomas and malignant melanomas tend to have a reduced hyaluronan content. In addition to the stroma-cancer cell interaction, hyaluronan can influence stromal cell recruitment, tumor angiogenesis and epithelial-mesenchymal transition. Hyaluronan receptors, hyaluronan synthases and hyaluronan degrading enzymes, hyaluronidases, are involved in the modulation of cancer progression, depending on the tumor type. Furthermore, intracellular signaling and angiogenesis are affected by the degradation products of hyaluronan. Hyaluronan has also therapeutic implications since it is involved in multidrug resistance.

  11. Metastatic malignant chondroblastoma.

    PubMed

    Rodgers, W B; Mankin, H J

    1996-12-01

    A case of malignant chondroblastoma with metastases is reported. The patient initially presented with a lytic lesion in his left pubic ramus. He was treated with curettage, but the lesion recurred 3 years later. After repeated curettage, radiation therapy, and the late development of multiple bone and soft-tissue metastases, he succumbed to his disease 13 years after diagnosis. The surgical pathology from each of his several procedures was reviewed. Although no definite malignant transformation was apparent, a metastatic deposit curetted 3 months prior to death showed some increase in mitotic activity. Flow cytometry of specimens from the patient's first local recurrence and a late distant metastasis was performed and revealed the interval development of a minor aneuploid peak between the two samples. This fatal chondroblastoma is the only one in our series of 80 patients treated over the past 25 years. PMID:9001683

  12. Nicotinamide Phosphoribosyltransferase in Malignancy

    PubMed Central

    Shackelford, Rodney E.; Mayhall, Kim; Maxwell, Nicole M.; Kandil, Emad

    2013-01-01

    Nicotinamide phosphoribosyltransferase (Nampt) catalyzes the rate-limiting step of nicotinamide adenine dinucleotide (NAD) synthesis. Both intracellular and extracellular Nampt (iNampt and eNampt) levels are increased in several human malignancies and some studies demonstrate increased iNampt in more aggressive/invasive tumors and in tumor metastases. Several different molecular targets have been identified that promote carcinogenesis following iNampt overexpression, including SirT1, CtBP, and PARP-1. Additionally, eNampt is elevated in several human cancers and is often associated with a higher tumor stage and worse prognoses. Here we review the roles of Nampt in malignancy, some of the known mechanisms by which it promotes carcinogenesis, and discuss the possibility of employing Nampt inhibitors in cancer treatment. PMID:24386506

  13. Lymphoscintigraphy in malignant melanoma

    SciTech Connect

    Berman, C.G.; Norman, J.; Cruse, C.W.; Reintgen, D.S.; Clark, R.A. )

    1992-01-01

    The development and rationale for the use of lymphoscintigraphy in the preoperative evaluation of patients with malignant melanoma being considered for elective lymph node dissection is reviewed. This overview is updated by an analysis of 135 patients with early stage malignant melanoma involving the head, neck, shoulders, and trunk at Moffitt Cancer Center and Research Institute at the University of South Florida (Tampa, FL). High discordancy rates (overall, 41%) were seen between drainage patterns predicted from historical anatomical guidelines and those revealed by the lymphoscintigraphic examination. The high discordancy rate was most pronounced in the head (64%) and the neck (73%). Surgical management was changed in 33% of the patients, overall. A preoperative lymphoscintigram is recommended for all patients with melanoma with head, neck, and truncal lesions evaluated for elective lymph node dissection as the lymphatic drainage patterns are often unpredictable and variable.

  14. Search for serendipitous Oort cloud object occultation in X-rays

    NASA Astrophysics Data System (ADS)

    Shang, Jie-Rou; Liu, Chih-Yuan; Chang, Hsiang-Kuang

    2015-08-01

    Serendipitous occultation search is a way to study small objects in the outer Solar system like trans-Neptunian objects (TNOs) by extracting and analyzing the diffraction pattern in the occultation lights. There are already some reported detections in both optical and X-ray bands in this kind of search. Except for KBOs, this method also has the potential to extend the search to a distance as far away as the Oort cloud region (beyond a few thousands AU). As the distance is larger, a shorter wavelength is needed to have a smaller Fresnel scale, with which occultation may be more easily detected. Here we introduce the serendipitous occultation method we used in searching Oort cloud objects occultation, and present the results of using Rossi X-ray Timing Explorer/Proportional Counter Array data of Sco X-1 taken from 1996 February to 2012 January.

  15. All-Sky Earth Occultation Observations with the Fermi Gamma Ray Burst Monitor

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, C. A.; Case, G.; Cherry, M.; Rodi, J.; Finger, M.; Camero-Arranz, A.; Chaplin, V.; Connaughton, V.; Berklen, E.; Haynes, R. H.; Bhat, P. N.; Briggs, M.; Preece, R.

    2009-01-01

    Using the Gamma Ray Burst Monitor (GBM) on-board Fermi, we are monitoring the hard X-ray/soft gamma ray sky using the Earth occultation technique. Each time a source in our catalog is occulted by (or exits occultation by) the Earth, we measure its flux by determining the change in count rate due to the occultation. Currently we are using CTIME data with 8 energy channels spanning 8 keV to 1 MeV for the GBM NaI detectors and spanning 150 keV to 40 MeV for the GBM BGO detectors. Our preliminary catalog consists of galactic X-ray binaries, the Crab Nebula, and active galactic nuclei. We will present early results. Regularly updated results can be found on our website http://gammaray.nsstc.nasa.gov/gbm/science/occultation.

  16. Implementation of the Earth-based planetary radio occultation inversion technique

    NASA Astrophysics Data System (ADS)

    Zhang, SuJun; Ping, JinSong; Han, TingTing; Mao, XiaoFei; Hong, ZhenJie

    2011-07-01

    The planetary radio occultation technique is one of the earliest suggested and achieved methods to detect the planetary atmosphere, and has been conducted by almost every deep space planetary probe. The principles, modules, inversion results and primary analysis of the SHAO Planetary Occultation observation Processing system (SPOPs) are presented in this paper. Utilizing open-loop and closed-loop Doppler residual data of the Mars Express radio occultation experiment provided by ESA PSA and NASA PDS, the temperature, pressure, molecular number density profiles of Martian atmosphere and electron density profiles of the ionosphere are successfully retrieved, and the results are validated by the released radio science level 04 products of the ESA MaRS group. This system can also process the atmosphere radio occultation observations of other planets and theirs natural satellites. The implementation of the planetary radio occultation technique is of significance to China's YH-1 Mars exploration project, as well as for future planetary exploration missions from China.

  17. James Webb Space Telescope Observations of Stellar Occultations by Solar System Bodies and Rings

    NASA Astrophysics Data System (ADS)

    Santos-Sanz, P.; French, R. G.; Pinilla-Alonso, N.; Stansberry, J.; Lin, Z.-Y.; Zhang, Z.-W.; Vilenius, E.; Müller, Th.; Ortiz, J. L.; Braga-Ribas, F.; Bosh, A.; Duffard, R.; Lellouch, E.; Tancredi, G.; Young, L.; Milam, Stefanie N.; the JWST “Occultations” Focus Group

    2016-01-01

    In this paper, we investigate the opportunities provided by the James Webb Space Telescope (JWST) for significant scientific advances in the study of Solar System bodies and rings using stellar occultations. The strengths and weaknesses of the stellar occultation technique are evaluated in light of JWST's unique capabilities. We identify several possible JWST occultation events by minor bodies and rings and evaluate their potential scientific value. These predictions depend critically on accurate a priori knowledge of the orbit of JWST near the Sun-Earth Lagrange point 2 (L2). We also explore the possibility of serendipitous stellar occultations by very small minor bodies as a byproduct of other JWST observing programs. Finally, to optimize the potential scientific return of stellar occultation observations, we identify several characteristics of JWST's orbit and instrumentation that should be taken into account during JWST's development.

  18. Asbestos-related malignancy.

    PubMed

    Talcott, J A; Antman, K H

    1988-01-01

    Asbestos-associated malignancies have received significant attention in the lay and medical literature because of the increasing frequency of two asbestos-associated tumors, lung carcinoma and mesothelioma; the wide distribution of asbestos; its status as a prototype environmental carcinogen; and the many recent legal compensation proceedings, for which medical testimony has been required. The understanding of asbestos-associated carcinogenesis has increased through study of animal models, human epidemiology, and, recently, the application of modern molecular biological techniques. However, the detailed mechanisms of carcinogenesis remain unknown. A wide variety of malignancies have been associated with asbestos, although the strongest evidence for a causal association is confined to lung cancer and mesothelioma. Epidemiological studies have provided evidence that both the type of asbestos fiber and the industry in which the exposure occurs may affect the rates of asbestos-associated cancers. It has been shown that asbestos exerts a carcinogenic effect independent of exposure to cigarette smoking that, for lung cancers, is synergistically enhanced by smoking. Other questions remain controversial, such as whether pulmonary fibrosis necessarily precedes asbestos-associated lung cancer and whether some threshold level of exposure to asbestos (including low-dose exposures that may occur in asbestos-associated public buildings) may be safe. Mesothelioma, the most closely asbestos-associated malignancy, has a dismal natural history and has been highly resistant to therapy. However, investigational multi-modality therapy may offer benefit to some patients. A description of the processes through which compensation claims for asbestos-associated malignancies are evaluated illustrates for physicians the legal system's approach to possible injury from toxic substances. The differences between scientific and legal reasoning about the causes of diseases with long latency

  19. Asbestos-related malignancy

    SciTech Connect

    Talcott, J.A.; Antman, K.H.

    1988-05-01

    Asbestos-associated malignancies have received significant attention in the lay and medical literature because of the increasing frequency of two asbestos-associated tumors, lung carcinoma and mesothelioma; the wide distribution of asbestos; its status as a prototype environmental carcinogen; and the many recent legal compensation proceedings, for which medical testimony has been required. The understanding of asbestos-associated carcinogenesis has increased through study of animal models, human epidemiology, and, recently, the application of modern molecular biological techniques. However, the detailed mechanisms of carcinogenesis remain unknown. A wide variety of malignancies have been associated with asbestos, although the strongest evidence for a causal association is confined to lung cancer and mesothelioma. Epidemiological studies have provided evidence that both the type of asbestos fiber and the industry in which the exposure occurs may affect the rates of asbestos-associated cancers. It has been shown that asbestos exerts a carcinogenic effect independent of exposure to cigarette smoking that, for lung cancers, is synergistically enhanced by smoking. Other questions remain controversial, such as whether pulmonary fibrosis necessarily precedes asbestos-associated lung cancer and whether some threshold level of exposure to asbestos (including low-dose exposures that may occur in asbestos-associated public buildings) may be safe. Mesothelioma, the most closely asbestos-associated malignancy, has a dismal natural history and has been highly resistant to therapy. However, investigational multi-modality therapy may offer benefit to some patients. 179 references.

  20. Epigenetics in the hematologic malignancies

    PubMed Central

    Fong, Chun Yew; Morison, Jessica; Dawson, Mark A.

    2014-01-01

    A wealth of genomic and epigenomic data has identified abnormal regulation of epigenetic processes as a prominent theme in hematologic malignancies. Recurrent somatic alterations in myeloid malignancies of key proteins involved in DNA methylation, post-translational histone modification and chromatin remodeling have highlighted the importance of epigenetic regulation of gene expression in the initiation and maintenance of various malignancies. The rational use of targeted epigenetic therapies requires a thorough understanding of the underlying mechanisms of malignant transformation driven by aberrant epigenetic regulators. In this review we provide an overview of the major protagonists in epigenetic regulation, their aberrant role in myeloid malignancies, prognostic significance and potential for therapeutic targeting. PMID:25472952

  1. Hemodynamic signature of breast cancer under fractional mammographic compression using a dynamic diffuse optical tomography system

    PubMed Central

    Carp, Stefan A.; Sajjadi, Amir Y.; Wanyo, Christy M.; Fang, Qianqian; Specht, Michelle C.; Schapira, Lidia; Moy, Beverly; Bardia, Aditya; Boas, David A.; Isakoff, Steven J.

    2013-01-01

    Near infrared dynamic diffuse optical tomography measurements of breast hemodynamics during fractional mammographic compression offer a novel contrast mechanism for detecting breast cancer and monitoring chemotherapy. Tissue viscoelastic relaxation during the compression period leads to a slow reduction in the compression force and reveals biomechanical and metabolic differences between healthy and lesion tissue. We measured both the absolute values and the temporal evolution of hemoglobin concentration during 25-35 N of compression for 22 stage II and III breast cancer patients scheduled to undergo neoadjuvant chemotherapy. 17 patients were included in the group analysis (average tumor size 3.2 cm, range: 1.3-5.7 cm). We observed a statistically significant differential decrease in total and oxy-hemoglobin, as well as in hemoglobin oxygen saturation in tumor areas vs. healthy tissue, as early as 30 seconds into the compression period. The hemodynamic contrast is likely driven by the higher tumor stiffness and different viscoelastic relaxation rate, as well as the higher tumor oxygen metabolism rate. PMID:24409390

  2. Mammographic density is the main correlate of tumors detected on ultrasound but not on mammography.

    PubMed

    Häberle, Lothar; Fasching, Peter A; Brehm, Barbara; Heusinger, Katharina; Jud, Sebastian M; Loehberg, Christian R; Hack, Carolin C; Preuss, Caroline; Lux, Michael P; Hartmann, Arndt; Vachon, Celine M; Meier-Meitinger, Martina; Uder, Michael; Beckmann, Matthias W; Schulz-Wendtland, Rüdiger

    2016-11-01

    Although mammography screening programs do not include ultrasound examinations, some diagnostic units do provide women with both mammography and ultrasonography. This article is concerned with estimating the risk of a breast cancer patient diagnosed in a hospital-based mammography unit having a tumor that is visible on ultrasound but not on mammography. A total of 1,399 women with invasive breast cancer from a hospital-based diagnostic mammography unit were included in this retrospective study. For inclusion, mammograms from the time of the primary diagnosis had to be available for computer-assisted assessment of percentage mammographic density (PMD), as well as Breast Imaging Reporting and Data System (BIRADS) assessment of mammography. In addition, ultrasound findings were available for the complete cohort as part of routine diagnostic procedures, regardless of any patient or imaging characteristics. Logistic regression analyses were conducted to identify predictors of mammography failure, defined as BIRADS assessment 1 or 2. The probability that the visibility of a tumor might be masked at diagnosis was estimated using a regression model with the identified predictors. Tumors were only visible on ultrasound in 107 cases (7.6%). PMD was the strongest predictor for mammography failure, but age, body mass index and previous breast surgery also influenced the risk, independently of the PMD. Risk probabilities ranged from 1% for a defined low-risk group up to 40% for a high-risk group. These findings might help identify women who should be offered ultrasound examinations in addition to mammography.

  3. Consumption of sweet foods and mammographic breast density: a cross-sectional study

    PubMed Central

    2014-01-01

    Background The increasing consumption of sugar worldwide seems to lead to several health problems, including some types of cancer. While some studies reported a positive association between sweet foods intake and breast cancer risk, little is known about their relation to mammographic density (MD), a strong breast cancer risk factor. This study examined the association of sweet foods and drinks intake with MD among 776 premenopausal and 779 postmenopausal women recruited at mammography. Methods A food-frequency questionnaire was used to assess intake of sweet foods, sugar-sweetened beverages and spoonsful of sugar added. Percent and absolute breast density were estimated using a computer-assisted method. Multivariate generalized linear models were used to evaluate associations. All models were adjusted for potential confounders, including age and body mass index. Results For increasing quartiles of sugar-sweetened beverages intake, adjusted-mean absolute density was respectively 32, 34, 32 and 36 cm2 among all women (Ptrend = 0.040) and 43, 46, 44 and 51 cm2 among premenopausal women (Ptrend = 0.007). For increasing quartiles of sweet foods intake, adjusted-mean percent density was respectively 16, 16, 17 and 19% among postmenopausal women (Ptrend = 0.036). No association was shown between intake of spoonsful of sugar added and MD. Conclusion Our results suggest that an increase in sweet foods or sugar-sweetened beverage intake is associated with higher MD. PMID:24969543

  4. A fully automated scheme for mammographic segmentation and classification based on breast density and asymmetry.

    PubMed

    Tzikopoulos, Stylianos D; Mavroforakis, Michael E; Georgiou, Harris V; Dimitropoulos, Nikos; Theodoridis, Sergios

    2011-04-01

    This paper presents a fully automated segmentation and classification scheme for mammograms, based on breast density estimation and detection of asymmetry. First, image preprocessing and segmentation techniques are applied, including a breast boundary extraction algorithm and an improved version of a pectoral muscle segmentation scheme. Features for breast density categorization are extracted, including a new fractal dimension-related feature, and support vector machines (SVMs) are employed for classification, achieving accuracy of up to 85.7%. Most of these properties are used to extract a new set of statistical features for each breast; the differences among these feature values from the two images of each pair of mammograms are used to detect breast asymmetry, using an one-class SVM classifier, which resulted in a success rate of 84.47%. This composite methodology has been applied to the miniMIAS database, consisting of 322 (MLO) mammograms -including 15 asymmetric pairs of images-, obtained via a (noisy) digitization procedure. The results were evaluated by expert radiologists and are very promising, showing equal or higher success rates compared to other related works, despite the fact that some of them used only selected portions of this specific mammographic database. In contrast, our methodology is applied to the complete miniMIAS database and it exhibits the reliability that is normally required for clinical use in CAD systems. PMID:21306782

  5. Predictive modeling of human perception subjectivity: feasibility study of mammographic lesion similarity

    NASA Astrophysics Data System (ADS)

    Xu, Songhua; Hudson, Kathleen; Bradley, Yong; Daley, Brian J.; Frederick-Dyer, Katherine; Tourassi, Georgia

    2012-02-01

    The majority of clinical content-based image retrieval (CBIR) studies disregard human perception subjectivity, aiming to duplicate the consensus expert assessment of the visual similarity on example cases. The purpose of our study is twofold: i) discern better the extent of human perception subjectivity when assessing the visual similarity of two images with similar semantic content, and (ii) explore the feasibility of personalized predictive modeling of visual similarity. We conducted a human observer study in which five observers of various expertise were shown ninety-nine triplets of mammographic masses with similar BI-RADS descriptors and were asked to select the two masses with the highest visual relevance. Pairwise agreement ranged between poor and fair among the five observers, as assessed by the kappa statistic. The observers' self-consistency rate was remarkably low, based on repeated questions where either the orientation or the presentation order of a mass was changed. Various machine learning algorithms were explored to determine whether they can predict each observer's personalized selection using textural features. Many algorithms performed with accuracy that exceeded each observer's self-consistency rate, as determined using a cross-validation scheme. This accuracy was statistically significantly higher than would be expected by chance alone (two-tailed p-value ranged between 0.001 and 0.01 for all five personalized models). The study confirmed that human perception subjectivity should be taken into account when developing CBIR-based medical applications.

  6. Predictive Modeling of Human Perception Subjectivity: Feasibility Study of Mammographic Lesion Similarity

    SciTech Connect

    Xu, Songhua; Tourassi, Georgia

    2012-01-01

    The majority of clinical content-based image retrieval (CBIR) studies disregard human perception subjectivity, aiming to duplicate the consensus expert assessment of the visual similarity on example cases. The purpose of our study is twofold: (i) discern better the extent of human perception subjectivity when assessing the visual similarity of two images with similar semantic content, and (ii) explore the feasibility of personalized predictive modeling of visual similarity. We conducted a human observer study in which five observers of various expertise were shown ninety-nine triplets of mammographic masses with similar BI-RADS descriptors and were asked to select the two masses with the highest visual relevance. Pairwise agreement ranged between poor and fair among the five observers, as assessed by the kappa statistic. The observers' self-consistency rate was remarkably low, based on repeated questions where either the orientation or the presentation order of a mass was changed. Various machine learning algorithms were explored to determine whether they can predict each observer's personalized selection using textural features. Many algorithms performed with accuracy that exceeded each observer's self-consistency rate, as determined using a cross-validation scheme. This accuracy was statistically significantly higher than would be expected by chance alone (two-tailed p-value ranged between 0.001 and 0.01 for all five personalized models). The study confirmed that human perception subjectivity should be taken into account when developing CBIR-based medical applications.

  7. Optimizing quality of digital mammographic imaging using Taguchi analysis with an ACR accreditation phantom.

    PubMed

    Chen, Ching-Yuan; Pan, Lung-Fa; Chiang, Fu-Tsai; Yeh, Da-Ming; Pan, Lung-Kwang

    2016-07-01

    This work demonstrated the improvement of the visualization of lesions by modulating the factors of an X-ray mammography imaging system using Taguchi analysis. Optimal combinations of X-ray operating factors in each group of level combination were determined using the Taguchi method, in which all factors were organized into only 18 groups, yielding analytical results with the same confidence as if each factor had been examined independently. The 4 considered operating factors of the X-ray machine were (1) anode material (target), (2) kVp, (3) mAs and (4) field of view (FOV). Each of these factors had 2 or 3 levels. Therefore, 54 (2×3×3×3 = 54) combinations were generated. The optimal settings were Rh as the target, 28 kVp, 80 mAs and 19×23 cm(2) FOV. The grade of exposed mammographic phantom image increased from the automatic exposure control (AEC) setting 70.92 to 72.00 under the optimal setting, meeting the minimum standard (70.00) set by Taiwan's Department of Health. The average glandular dose (AGD) of the exposed phantom, 0.182 cGy, was lower than that, 0.203 cGy, under the AEC setting. The Taguchi method was extremely promising for the design of imaging protocols in clinical diagnosis. PMID:27282343

  8. Classification of mammographic masses: comparison between Backpropagation Neural Network (BNN) and human readers

    NASA Astrophysics Data System (ADS)

    Arbach, Lina; Bennett, Darus L.; Reinhardt, Joseph M.; Fallouh, Ghassan

    2003-05-01

    PURPOSE: We compare mammographic mass classification performance between a backpropagation neural network (BNN), expert radiologists, and residents. Our goal is to reduce false negatives during routine reading of mammograms. METHODS: 160 cases from 3 different institutions were used. Each case contained at least one mass and had an accompanying biopsy result. Masses were extracted using region growing with seed locations identified by an expert radiologist. 10 texture and shape based features (area, perimeter, compactness, radial length, spiculation, mean/standard deviation of radial length, minimum/maximum axis, and boundary roughness) were used as inputs to a three-layer BNN. Shape features were computed on the boundary of the mass region; texture features were computed from the pixel values inside the mass. 140 cases were used for training the BNN and the remaining 20 cases were used for testing. The testing set was diagnosed by three expert radiologists, three residents, and the BNN. We evaluated the human readers and the BNN by computing the area under the ROC curve (AUC). RESULTS: The AUC was 0.923 for the BNN, 0.846 for the expert radiologists, and 0.648 for the residents. These results illustrate the promise of using BNN as a physician"s assistant for breast mass classification.

  9. Mammographic density is the main correlate of tumors detected on ultrasound but not on mammography.

    PubMed

    Häberle, Lothar; Fasching, Peter A; Brehm, Barbara; Heusinger, Katharina; Jud, Sebastian M; Loehberg, Christian R; Hack, Carolin C; Preuss, Caroline; Lux, Michael P; Hartmann, Arndt; Vachon, Celine M; Meier-Meitinger, Martina; Uder, Michael; Beckmann, Matthias W; Schulz-Wendtland, Rüdiger

    2016-11-01

    Although mammography screening programs do not include ultrasound examinations, some diagnostic units do provide women with both mammography and ultrasonography. This article is concerned with estimating the risk of a breast cancer patient diagnosed in a hospital-based mammography unit having a tumor that is visible on ultrasound but not on mammography. A total of 1,399 women with invasive breast cancer from a hospital-based diagnostic mammography unit were included in this retrospective study. For inclusion, mammograms from the time of the primary diagnosis had to be available for computer-assisted assessment of percentage mammographic density (PMD), as well as Breast Imaging Reporting and Data System (BIRADS) assessment of mammography. In addition, ultrasound findings were available for the complete cohort as part of routine diagnostic procedures, regardless of any patient or imaging characteristics. Logistic regression analyses were conducted to identify predictors of mammography failure, defined as BIRADS assessment 1 or 2. The probability that the visibility of a tumor might be masked at diagnosis was estimated using a regression model with the identified predictors. Tumors were only visible on ultrasound in 107 cases (7.6%). PMD was the strongest predictor for mammography failure, but age, body mass index and previous breast surgery also influenced the risk, independently of the PMD. Risk probabilities ranged from 1% for a defined low-risk group up to 40% for a high-risk group. These findings might help identify women who should be offered ultrasound examinations in addition to mammography. PMID:27389655

  10. Evolution of mammographic image quality in the state of Rio de Janeiro*

    PubMed Central

    Villar, Vanessa Cristina Felippe Lopes; Seta, Marismary Horsth De; de Andrade, Carla Lourenço Tavares; Delamarque, Elizabete Vianna; de Azevedo, Ana Cecília Pedrosa

    2015-01-01

    Objective To evaluate the evolution of mammographic image quality in the state of Rio de Janeiro on the basis of parameters measured and analyzed during health surveillance inspections in the period from 2006 to 2011. Materials and Methods Descriptive study analyzing parameters connected with imaging quality of 52 mammography apparatuses inspected at least twice with a one-year interval. Results Amongst the 16 analyzed parameters, 7 presented more than 70% of conformity, namely: compression paddle pressure intensity (85.1%), films development (72.7%), film response (72.7%), low contrast fine detail (92.2%), tumor mass visualization (76.5%), absence of image artifacts (94.1%), mammography-specific developers availability (88.2%). On the other hand, relevant parameters were below 50% conformity, namely: monthly image quality control testing (28.8%) and high contrast details with respect to microcalcifications visualization (47.1%). Conclusion The analysis revealed critical situations in terms of compliance with the health surveillance standards. Priority should be given to those mammography apparatuses that remained non-compliant at the second inspection performed within the one-year interval. PMID:25987749

  11. Inter-observer variability within BI-RADS and RANZCR mammographic density assessment schemes

    NASA Astrophysics Data System (ADS)

    Damases, Christine N.; Mello-Thoms, Claudia; McEntee, Mark F.

    2016-03-01

    This study compares variability associated with two visual mammographic density (MD) assessment methods using two separate samples of radiologists. The image test-set comprised of images obtained from 20 women (age 42-89 years). The images were assessed for their MD by twenty American Board of Radiology (ABR) examiners and twenty-six radiologists registered with the Royal Australian and New Zealand College of Radiologists (RANZCR). Images were assessed using the same technology and conditions, however the ABR radiologists used the BI-RADS and the RANZCR radiologists used the RANZCR breast density synoptic. Both scales use a 4-point assessment. The images were then grouped as low- and high-density; low including BIRADS 1 and 2 or RANZCR 1 and 2 and high including BI-RADS 3 and 4 or RANZCR 3 and 4. Four-point BI-RADS and RANZCR showed no or negligible correlation (ρ=-0.029 p<0.859). The average inter-observer agreement on the BI-RADS scale had a Kappa of 0.565; [95% CI = 0.519 - 0.610], and ranged between 0.328-0.669 while the inter-observer agreement using the RANZCR scale had a Kappa of 0.360; [95% CI = 0.308 - 0.412] and a range of 0.078-0.499. Our findings show a wider range of inter-observer variability among RANZCR registered radiologists than the ABR examiners.

  12. Fluorescence detection of premalignant, malignant, and micrometastatic disease using hexylpyropheophorbide

    NASA Astrophysics Data System (ADS)

    Furukawa, Kinya; Crean, David H.; Mang, Thomas S.; Kato, Harubumi; Dougherty, Thomas J.

    1995-03-01

    We investigated the in vivo fluorescence detection of premalignant and malignant lesions in carcinogen-induced tumors of the hamster buccal cheek pouch and micrometastases in rat lymph nodes using hexylpyropheophorbide-a (HPPH) at 0.5 mg/kg and He-Ne laser-induced fluorescence photometry. Time course studies of HPPH in hamster tumor model showed maximal relative fluorescence readings at 48 hours after i.p. injection in each stage (dysplasia: 0.35, papilloma: 0.58, squamous cell carcinoma: 1.04). Squamous cell carcinoma showed significantly greater fluorescence than papillomas and dysplasias at all time points (p < 0.01). Metastatic lymph nodes were significantly greater than normal lymph nodes at all time points (p < 0.01). Maximal fluorescence levels of normal lymph nodes were observed at 6 hours after i.v. injection. Metastatic lymph nodes still showed high fluorescence levels at 72 hours. Micrometastases showed fluorescence levels between the levels of metastatic and normal lymph nodes (normal: 0.40 < micrometastasis: 0.62 < metastasis: 0.75 at 48 hours after i.v. injection). The results demonstrated good correlation between fluorescence levels and histopathological developments at all time points. Therefore, HPPH may be a promising fluorophore for the detection of developing malignancies and occult disease.

  13. Image guidance improves localization of sonographically occult colorectal liver metastases

    NASA Astrophysics Data System (ADS)

    Leung, Universe; Simpson, Amber L.; Adams, Lauryn B.; Jarnagin, William R.; Miga, Michael I.; Kingham, T. Peter

    2015-03-01

    Assessing the therapeutic benefit of surgical navigation systems is a challenging problem in image-guided surgery. The exact clinical indications for patients that may benefit from these systems is not always clear, particularly for abdominal surgery where image-guidance systems have failed to take hold in the same way as orthopedic and neurosurgical applications. We report interim analysis of a prospective clinical trial for localizing small colorectal liver metastases using the Explorer system (Path Finder Technologies, Nashville, TN). Colorectal liver metastases are small lesions that can be difficult to identify with conventional intraoperative ultrasound due to echogeneity changes in the liver as a result of chemotherapy and other preoperative treatments. Interim analysis with eighteen patients shows that 9 of 15 (60%) of these occult lesions could be detected with image guidance. Image guidance changed intraoperative management in 3 (17%) cases. These results suggest that image guidance is a promising tool for localization of small occult liver metastases and that the indications for image-guided surgery are expanding.

  14. Comparison of ionospheric radio occultation CHAMP data with IRI 2000

    NASA Astrophysics Data System (ADS)

    Jakowski, N.; Wehrenpfennig, A.; Tsybulya, K.

    The GPS radio occultations measured on board low Earth orbiting satellites provide vertical electron density profiles of the ionosphere from satellite orbit heights down to the bottomside. No other profiling technique unifies profiling through the entire F2 layer with global coverage. First results of ionospheric radio occultation (IRO) measurements carried out onboard the German CHAMP satellite mission agree with vertical sounding based F2 layer height and electron density estimations within 13% and 17% RMS deviation. Methods and algorithms applied for retrieving the electron density profiles through the F2 layer are addressed. Although the validation of the CHAMP IRO data has still to be completed, we present a systematic comparison of more than 15000 IRO derived electron density profiles with corresponding IRI 2000 estimations. The results are discussed for quite different geophysical conditions, e.g. as a function of local time, season, geomagnetic/geographic latitude, level of geomagnetic activity. For a limited umber of events both types of electron density profiles are compared with independent electron density data obtained from vertical sounding stations on Earth and from the Langmuir probe onboard CHAMP.

  15. Scattered Signal Observations During Cassini Radio Occultations by Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Thomson, F.; Wong, K.; Marouf, E.; Rappaport, N.; French, R.; McGhee, C.

    2005-12-01

    Eight Cassini radio occultations of Saturn's rings were conducted between May 3 and September 5, 2005. During any given occultation, Cassini transmits through the rings three coherent sinusoidal radio signals of wavelength 0.94, 3.6, and 13 cm (Ka-, X-, and S-band, respectively). Spectral analysis of the signals received at the NASA Deep Space Network (DSN) reveals two distinct signal components. The first component is the direct signal, the remnant of the incident sinusoid reduced in amplitude and shifted in phase. The second component is the near-forward scattered signal, which is a frequency-broadened by the Doppler shift introduced by the relative motion of the spacecraft and ring particles. The scattered component is clearly detectable at all three observation wavelengths and for most ring features, with the exception of the optically thick subregions in Ring B where the radio signals were essentially blocked. This is the first time ever near-forward scattered signals are observed at three radio bands simultaneously. We present observed spectrograms of the Ka/X/S-band signals across the full ring system and characterize their relationship to observed ring structure. We also present results of preliminary analysis of the implications of the observations for the particle size distribution and microstructure of selected ring features.

  16. Dust occultation at Titan measured by CDA onboard Cassini

    NASA Astrophysics Data System (ADS)

    Srama, Ralf; CDA science team

    2016-10-01

    The Cosmic Dust Analyzer (CDA) onboard Cassini characterized successfully the dust environment at Saturn since 2004. The instrument measures the primary charge, speed, mass and composition of individual submicron and micron sized dust grains. The detection threshold scales with speed^3.5 such that the detection of fast nanograins (~100 km/s) is possible. Saturn's nanodust environment (streams) is studied many years. However, a special geometric condition of Saturn, Cassini and Titan during a Titan flyby in 2014 (DOY 65) provided a special dust occultation opportunity. Titan and its atmosphere blocked the stream of fast nanoparticles such that CDA registered a clear drop in impact rate around closest approach. An analysis of the data allows to constrain the source region of the nanograins, which is compatible with a source region in the ring plane at distances from Saturn between 4 and 8 Saturn radii. Backward and forward modeling was performed leading to dust grain sizes between 3 and 9 nm and speeds between 80 and 150 km/s. The new modeling results also show that Enceladus acts a direct source for nanodust streams leading to the observation of periodic impact rates in the outer Saturn system. Such periodicities were observed recently by CDA and showed a clear signature of the Enceladus orbital period. A second dust occultation opportunity using Titan is planned august 2016.

  17. The ionosphere of Europa from Galileo radio occultations.

    PubMed

    Kliore, A J; Hinson, D P; Flasar, F M; Nagy, A F; Cravens, T E

    1997-07-18

    The Galileo spacecraft performed six radio occultation observations of Jupiter's Galilean satellite Europa during its tour of the jovian system. In five of the six instances, these occultations revealed the presence of a tenuous ionosphere on Europa, with an average maximum electron density of nearly 10(4) per cubic centimeter near the surface and a plasma scale height of about 240 +/- 40 kilometers from the surface to 300 kilometers and of 440 +/- 60 kilometers above 300 kilometers. Such an ionosphere could be produced by solar photoionization and jovian magnetospheric particle impact in an atmosphere having a surface density of about 10(8) electrons per cubic centimeter. If this atmosphere is composed primarily of O2, then the principal ion is O2+ and the neutral atmosphere temperature implied by the 240-kilometer scale height is about 600 kelvin. If it is composed of H2O, the principal ion is H3O+ and the neutral temperature is about 340 kelvin. In either case, these temperatures are much higher than those observed on Europa's surface, and an external heating source from the jovian magnetosphere is required. PMID:9219689

  18. 'Trick', 'manipulation' and 'farce': Albert Moll's critique of occultism.

    PubMed

    Wolffram, Heather

    2012-04-01

    In July 1925, the psychiatrist Albert Moll appeared before the district court in Berlin-Schöneberg charged with having defamed the medium Maria Vollhardt (alias Rudloff) in his 1924 book Der Spiritismus [Spiritism]. Supported by some of Berlin's most prominent occultists, the plaintiff--the medium's husband--argued that Moll's use of terms such as 'trick', 'manipulation' and 'farce' in reference to Vollhardt's phenomena had been libellous. In the three-part trial that followed, however, Moll's putative affront to the medium--of which he was eventually acquitted--was overshadowed, on the one hand, by a debate over the scientific status of parapsychology, and on the other, by the question of who--parapsychologists, occultists, psychiatrists or jurists--was entitled to claim epistemic authority over the occult. This paper will use the Rudloff-Moll trial as a means of examining Moll's critique of occultism, not only as it stood in the mid-1920s, but also as it had developed since the 1880s. It will also provide insight into the views of Germany's occultists and parapsychologists, who argued that their legitimate bid for scientific credibility was hindered by Dunkelmänner [obscurantists] such as Albert Moll.

  19. Stargazing from New Horizons: Ultraviolet Stellar Occultations by Pluto's Atmosphere

    NASA Astrophysics Data System (ADS)

    Kammer, Joshua A.; Stern, S. Alan; Weaver, Harold A.; Young, Leslie; Ennico, Kimberly; Olkin, Catherine B.; Gladstone, Randy; Summers, Michael; Steffl, Andrew; Greathouse, Thomas K.; Versteeg, Maarten; Retherford, Kurt D.; Parker, Joel Wm.; Schindhelm, Eric; Strobel, Darrell F.; New Horizons ATM Theme Team, New Horizons Science Team

    2016-10-01

    Not long after the New Horizons encounter with Pluto last July, the Alice ultraviolet imaging spectrograph observed signatures of UV absorption by Pluto's atmosphere during two distinct occultation events. During these events, UV bright stars (the Sun, as well as two B-type stars) passed behind Pluto as seen by the spacecraft, and the attenuated starlight revealed the clear presence of nitrogen, methane, and several other hydrocarbons. Their mixing ratios vary with altitude, including localized peaks in the density of minor hydrocarbons such as C2H2 and C2H4. At about 300 km above Pluto's surface, these particular species are found to have mixing ratios relative to CH4 of approximately 10% and 1%, respectively. While this overall composition was expected pre-New Horizons, the vertical profiles of these species were surprising. In this presentation I will discuss the analysis of these occultations, including several profiles of key atmospheric species, and how they might play a role in explaining the presence of high-altitude haze on this cold, small, distant planet.

  20. Progress in Turbulence Detection via GNSS Occultation Data

    NASA Technical Reports Server (NTRS)

    Cornman, L. B.; Goodrich, R. K.; Axelrad, P.; Barlow, E.

    2012-01-01

    The increased availability of radio occultation (RO) data offers the ability to detect and study turbulence in the Earth's atmosphere. An analysis of how RO data can be used to determine the strength and location of turbulent regions is presented. This includes the derivation of a model for the power spectrum of the log-amplitude and phase fluctuations of the permittivity (or index of refraction) field. The bulk of the paper is then concerned with the estimation of the model parameters. Parameter estimators are introduced and some of their statistical properties are studied. These estimators are then applied to simulated log-amplitude RO signals. This includes the analysis of global statistics derived from a large number of realizations, as well as case studies that illustrate various specific aspects of the problem. Improvements to the basic estimation methods are discussed, and their beneficial properties are illustrated. The estimation techniques are then applied to real occultation data. Only two cases are presented, but they illustrate some of the salient features inherent in real data.

  1. The occultation of gamma Geminorum by the asteroid 381 Myrrha

    NASA Astrophysics Data System (ADS)

    Sato, I.; Soma, M.; Hirose, T.

    1993-04-01

    The occultation of Gamma Geminorum by asteroid 381 Myrrha on January 13, 1991, observed in Japan and China, was the brightest event ever seen of a stellar occultation by an asteroid. By the analysis of the timing data of this event measured in Japan, it is shown that the cross section of Myrrha is well fitted with an ellipse of (147.2 +/- 2.4) km x (126.6 +/- 7.9) km. An upper limit of the diameter of Gamma Geminorum is also estimated to be 2.6 milliarcsec. The companion of Gamma Geminorum of about 7.5 mag was sited at separation (64 +/- 8) milliarcsec in the direction P = 129 deg +/- 59 deg, and the relative position of Myrrha to Gamma Geminorum was determined to an accuracy of about 1 milliarcsec. Direct constraints on Myrrha's 3D shape and the direction of its rotation axis are obtained on the assumption of it being a triaxial ellipsoid with isotropic orientation.

  2. [IMMUNOPATHOGENESIS OF OCCULT INFECTION CAUSED BY HEPATITIS B VIRUS].

    PubMed

    Semenenko, T A; Suslov, A P

    2015-01-01

    The concept of occult infection caused by hepatitis B virus (HBV) is determined as the presence of HBV DNA in blood sera or liver with the absence of detectable HBsAg. The actuality of this problem is associated with the fact, that occult hepatitis B (OHB) can be transmitted during hemotransfusions, cause reactivation of chronic hepatitis B in immune compromised individuals, facilitate development of liver cirrhosis and hepatocellular carcinoma. Several different hypotheses of OHB immunopathogenesis have been proposed, including a low number of copies of HBV DNA, altered immune response of the macroorganism, genetic variability of the S gene, integration of viral DNA into host genome, infection of mononuclear cells of peripheral blood, presence of immune complexes that hide HBsAg, and interference by other viruses such as HCV and HIV. Molecular mechanisms of HBV virus in HBsAg-negative individuals are not fully understood, however, viral mutations seem a very significant factor. Approaches of OHB prophylaxis including use of a polyvalent vaccine, that allows vaccination against wild and mutant HBV viruses, are examined. PMID:26950999

  3. Radio occultation data analysis by the radioholographic method

    NASA Astrophysics Data System (ADS)

    Hocke, K.; Pavelyev, A. G.; Yakovlev, O. I.; Barthes, L.; Jakowski, N.

    1999-10-01

    The radioholographic method is briefly described and tested by using data of 4 radio occultation events observed by the GPS/MET experiment on 9 February 1997. The central point of the radioholographic method (Pavelyev, 1998) is the generation of a radiohologram along the LEO satellite trajectory which allows the calculation of angular spectra of the received GPS radio wave field at the LEO satellite. These spectra are promising in view of detection, analysis and reduction of multipath/diffraction effects, study of atmospheric irregularities and estimation of bending angle error. Initial analysis of angular spectra calculated by the multiple signal classification (MUSIC) method gives evidence that considerable multibeam propagation occurs at ray perigee heights below 20 km and at heights around 80-120 km for the 4 GPS/MET occultation events. Temperature profiles obtained by our analysis (radioholographic method, Abel inversion) are compared with those of the traditional retrieval by the UCAR GPS/MET team (bending angle from slope of phase front, Abel inversion). In 3 of 4 cases we found good agreement (standard deviation σT~1.5°K between both retrievals at heights 0-30 km).

  4. The ATOMMS Radio Occultation Climate Remote Sensing System

    NASA Astrophysics Data System (ADS)

    Kursinski, E. R.; Otarola, A. C.; Ward, D.; McGhee, J.; Reed, H.; Walden, L.

    2012-12-01

    Increasingly complex computer models approximate the climate system and make predictions about how climate will change. In order to make informed decisions about what to do about climate change, one must know how trustworthy these predictions are. Assessing the accuracy of the models and their predictions can only come from comparing models with observations of the real climate. Therefore, we must have observations that precisely and unambiguously determine the state of the climate system, and they must do so independently from the atmospheric models they are being compared against. While this is a very basic point of logic, it is quite difficult to achieve in practice because of the difficulties and limitations of the observations. For this purpose we have been developing a new orbiting remote sensing system called the Active Temperature, Ozone and Moisture Microwave Spectrometer (ATOMMS) that is a cross between GPS radio occultation and the Microwave Limb Sounder (MLS). Unlike GPS which uses wavelengths that minimize interaction with the atmosphere, ATOMMS actively probes water vapor and other absorption lines at cm and mm wavelengths in an occultation geometry to simultaneously profile temperature and water vapor. During each occultation, ATOMMS measures the changes in signal amplitude and frequency caused by passage through the atmosphere relative to the amplitude and frequency measured less than 100 seconds earlier when the signal path was above the atmosphere. As such, the ATOMMS observations are inherently self-calibrating. Furthermore, unlike the inherently ambiguous and non-unique atmospheric profiles retrieved from thermal radiance measurements, the atmospheric profiles retrieved from occultations are unique. The expected accuracy of individual ATOMMS profiles of water vapor, temperature and pressure heights is approximately 1%, 0.4K and 10 m respectively with 200 m or better vertical resolution. Performance in cloudy areas will be within a factor of 2 of

  5. Population-based colorectal cancer screening: comparison of two fecal occult blood test

    PubMed Central

    Zubero, Miren B.; Arana-Arri, Eunate; Pijoan, José I.; Portillo, Isabel; Idigoras, Isabel; López-Urrutia, Antonio; Samper, Ana; Uranga, Begoña; Rodríguez, Carmen; Bujanda, Luis

    2014-01-01

    Background: The aim of screening for colorectal cancer is to improve prognosis by the detection of cancer at its early stages. In order to inform the decision on the specific test to be used in the population-based program in the Basque Autonomous Region (Spain), we compared two immunochemical fecal occult blood quantitative tests (I-FOBT). Methods: Residents of selected study areas, aged 50–69 years, were invited to participate in the screening. Two tests based on latex agglutination (OC-Sensor and FOB Gold) were randomly assigned to different study areas. A colonoscopy was offered to patients with a positive test result. The cut-off point used to classify a result as positive, according to manufacturer’s recommendations, was 100 ng/ml for both tests. Results: The invited population included 37,999 individuals. Participation rates were 61.8% (n = 11,162) for OC-Sensor and 59.1% (n = 11,786) for FOB Gold (p = 0.008). Positive rate for OC-Sensor was 6.6% (n = 737) and 8.5% (n = 1,002) for FOB Gold (p < 0.0001). Error rates were higher for FOB gold (2.3%) than for OC-Sensor (0.2%; p < 0.0001). Predictive positive value (PPV) for total malignant and premalignant lesions was 62.4% for OC-Sensor and 58.9% for FOB Gold (p = 0.137), respectively. Conclusion: OC-Sensor test appears to be superior for I-FOBT-based colorectal cancer screening, given its acceptance, ease of use, associated small number of errors and its screening accuracy. FOB Gold on the other hand, has higher rate of positive values, with more colonoscopies performed, it shows higher detection incidence rates, but involves more false positives. PMID:24454288

  6. Malignant testicular tumours

    PubMed Central

    Vecchio, Pierre Del; Tawil, Elie; Béland, Gilles

    1974-01-01

    A series of 71 patients with malignant testicular tumours treated primarily by orchiectomy and irradiation is reviewed with respect to pathological and clinical features and modes of treatment. The three-year crude survival rate in 36 patients with seminoma was 86% and in 24 patients with carcinoma it was 41.7%. There were no survivors among patients with choriocarcinoma. Our results are comparable with those of other series. A prospective study is proposed of the value of irradiation and subsequent limited lymph node dissection following orchiectomy in cases of carcinoma of the testis. PMID:4855670

  7. Intraoral malignant melanoma

    PubMed Central

    Babburi, Suresh; Subramanyam, R. V.; Aparna, V.; Sowjanya, P.

    2013-01-01

    Primary oral mucosal melanoma is a rare aggressive neoplasm and accounts for only 0.2-8% of all reported melanomas. It is a malignant neoplasm of melanocytes that may arise from a benign melanocytic lesion or de novo from melanocytes within normal skin or mucosa. It is considered to be the most deadly and biologically unpredictable of all human neoplasms, having the worst prognosis. In this article, we report a case of oral melanoma in a 52-year-old female patient with a chief complaint of black discolouration of the maxillary gingiva and palate. PMID:24249959

  8. All-Sky Earth Occultation Observations with the Fermi Gamma Ray Burst Monitor

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, C. A.; Beklen, E.; Bhat, P. N.; Briggs, M.; Camero-Arranz, A.; Case, G.; Chaplin, V.; Cherry, M.; Connaughton, V.; Finger, M.; Jenke, P.; Paciesas, W.; Preece, R.; Rodi, J.

    2010-01-01

    Using the Gamma Ray Burst Monitor (GBM) on-board Fermi, we are monitoring the hard X-ray/soft gamma ray sky using the Earth occultation technique. Each time a source in our catalog is occulted by (or exits occultation by) the Earth, we measure its flux using the change in count rates due to the occultation. Currently we are using CTIME data with 8 energy channels spanning 8 keV to 1 MeV for the GBM NaI detectors and spanning 150 keV to 40 MeV for the GBM BGO detectors. Our preliminary catalog consists of galactic X-ray binaries, the Crab Nebula, and active galactic nuclei. New sources are added to our catalog as they become active or upon request. In addition to Earth occultations, we have observed numerous occultations with Fermi's solar panels. We will present early results. Regularly updated results will be found on our website http://gammaray.nsstc.nasa.gov/gbm/science/occultation.

  9. Development and Performance of the PHOT (Portable High-Speed Occultation Telescope) Systems

    NASA Astrophysics Data System (ADS)

    Young, E. F.; Young, L. A.; Olkin, C. B.; Buie, M. W.; Shoemaker, K.; French, R. G.; Regester, J.

    2011-06-01

    The PHOT (Portable High-Speed Occultation Telescope) systems were developed for the specific purpose of observing stellar occultations by solar system objects. Stellar occultations have unique observing constraints: they may only be observable from certain parts of the globe; they often require a rapid observing cadence; and they require accurate time-stamp information for each exposure. The PHOT systems consist of 14 inch telescopes, CCD cameras, camera mounting plates, GPS-based time standards, and data acquisition computers. The PHOT systems are similar in principle to the POETS systems (Portable Occultation, Eclipse, and Transit Systems), with the main differences being (1) different CCD cameras with slightly different specifications and (2) a standalone custom-built time standard used by PHOT, whereas POETS uses a commercial time standard that is controlled from a computer. Since 2005, PHOT systems have been deployed on over two-dozen occasions to sites in the US, Mexico, Chile, Namibia, South Africa, France, Austria, Switzerland, Australia, and New Zealand, mounted on portable 14 inch telescopes or on larger stationary telescopes. Occultation light curves acquired from the 3.9 m AAT (Anglo-Australian Telescope) have produced photometric signal-to-noise ratios (S/N) of 333 per scale height for a stellar occultation by Pluto. In this article we describe the seven PHOT subsystems in detail (telescopes, cameras, timers, and data stations) and present S/N estimates for actual and predicted occultations as functions of star brightness, telescope aperture, and frame rate.

  10. A pareto-optimal characterization of miniaturized distributed occulter/telescope systems

    NASA Astrophysics Data System (ADS)

    Koenig, Adam W.; D'Amico, Simone; Macintosh, Bruce; Titus, Charles J.

    2015-09-01

    Distributed occulter/telescope systems hold great promise in the field of direct exoplanet imaging. However, proposed missions using this concept such as the New Worlds Observer or Exo-S (NASA) are exceptionally large with occulter diameters of tens of meters and inter-spacecraft separations of tens of megameters, requiring deployment in deep space. The estimated costs associated with these missions are in the billions of dollars. In order to reduce the risk associated with these missions, it is desirable to first deploy a low-cost technology demonstrator mission to prove that the distributed occulter telescope concept is valid. To that end, this work assesses the feasibility of miniaturizing the optics of the distributed occulter/telescope to enable deployment on micro- or nano-satellites in earth orbit. A variant of the convex optimization formulation introduced by previous authors is used to generate a pareto-optimal characterization between the achievable occulter contrast and a set of critical design variables (occulter radius, inner working angle, science spectrum, etc). This characterization is performed for two different sets of engineering constraints, corresponding to different levels of design complexity. The results of this study are compared to the performance requirements for imaging targets of scientific interest, namely exozodiacal dust disks, in order to identify promising design envelopes. The result of this work is a comprehensive trade of the capabilities of miniaturized, binary, petal-shaped occulters. This research demonstrates that there exist miniaturized occulter geometries compatible with micro- or nano-satellites in earth orbit suitable for imaging exozodiacal dust disks. In addition, this study provides a valuable methodology and performance guidelines for future distributed occulter/telescope designs.

  11. [Stellar Occultation Studies of Small Bodies in the Outer Solar System: Accomplishments, Status, and Plans

    NASA Technical Reports Server (NTRS)

    Elliott, James

    2005-01-01

    Bodies residing in the outer solar system exhibit unique physical processes, and some of the lessons learned from them can be applied to understanding what occurred in the outer solar system during its formation and early evolution. Pluto, the largest known Kuiper Belt object (KBO), and its near twin Triton--an ex-KBO that has been captured by Neptune--have nitrogen atmospheres that are in vapor-pressure equilibrium with surface ice. These atmospheres are most sensitively probed from Earth by the technique of Stellar occultations, which can provide the temperature and pressure profiles of these atmospheres at a spatial resolution of a few kilometers. Recent results from occultations show that the surface pressure of Triton's atmosphere has been increasing and that the shape of the atmosphere deviates from its expected spherical figure. With the occultation technique we can also learn the sizes of smaller bodies that have formed in the outer solar system: Charon, the Centaurs, and KBOs. Our proposed program involves identifying occultation candidates, predicting occultations, observing occultations, analysis of the data, and synthesis of the occultation results with other data. The main goals for our proposed work are to (i) further observe occultations by Triton with the objectives of understanding its pressure changes, distortion, and enigmatic thermal structure (ii) determine whether the abrupt drop in Pluto's stellar occultation light curve is caused by a sharp thermal gradient near its surface or by atmospheric haze, (iii) further observations to characterize the potential collapse of Pluto's atmosphere as it recedes from the sun (information that should be of interest to the Pluto-Kuiper Express), ( iv ) determine Charon's radius more accurately than can be done with the mutual events to derive a better estimate of Charon's density, and ( v ) directly determine the size (and albedo) of Centaurs with the goal of more accurately estimating the sizes of KBOS.

  12. Pleural malignancies including mesothelioma.

    PubMed

    Hillerdal, G

    1995-07-01

    Malignant mesothelioma is caused almost exclusively by occupational exposure to asbestos. During the past few years, however, increasing evidence has mounted that background exposure to asbestos could be sufficient to cause mesothelioma. Treatment of malignant mesothelioma remains a big problem. Some new approaches are on their way, and the most exciting ones are local immunotherapy in very early cases. Some success has been reported with local interferon treatment. As for treatment of metastatic pleural disease, the main purpose is symptomatic relief of dyspnea caused by fluid accumulation. The best way to achieve a lasting palliation is pleurodesis, and the most common way to do this, is by chemical means. The drug of choice in the United States has for many years been tetracycline, but since injectable tetracycline is no longer available, some substitute must be found. The substance that will "win" is not yet clear, but the two leading contestants are talc and doxycycline. Bleomycin also has its supporters, and a dark horse is quinacrine, which although not easily available in the United States, has been used in many European centers for decades. PMID:9363074

  13. Malignant pleural mesothelioma.

    PubMed

    Boutin, C; Schlesser, M; Frenay, C; Astoul, P

    1998-10-01

    The incidence of malignant pleural mesothelioma (MPM) has risen for some decades and is expected to peak between 2010 and 2020. Up to now, no single treatment has been proven to be effective and death usually occurs within about 12-17 months after diagnosis. Perhaps because of this poor prognosis, early screening has incited little interest. However, certain forms may have a better prognosis when diagnosed early and treated by multimodal therapy or intrapleural immunotherapy. Diagnosis depends foremost on histological analysis of samples obtained by thoracoscopy. This procedure allows the best staging of the pleural cavity with an attempt to detect visceral pleural involvement, which is one of the most important prognostic factors. Although radiotherapy seems necessary and is efficient in preventing the malignant seeding after diagnostic procedures in patients, there has been no randomized phase III study showing the superiority of any treatment compared with another. However, for the early-stage disease (stage I) a logical therapeutic approach seems to be neoadjuvant intrapleural treatment using cytokines. For more advanced disease (stages II and III) resectability should be discussed with the thoracic surgeons and a multimodal treatment combining surgery, radiotherapy and chemotherapy should be proposed for a randomized controlled study. Palliative treatment is indicated for stage IV. In any case, each patient should be enrolled in a clinical trial.

  14. Radio Occultation Measurements of Pluto's Atmosphere with New Horizons

    NASA Astrophysics Data System (ADS)

    Hinson, David P.; Linscott, Ivan; Young, Leslie; Stern, S. Alan; Bird, Mike; Ennico, Kimberly; Gladstone, Randy; Olkin, Catherine B.; Pätzold, Martin; Strobel, Darrell F.; Summers, Michael; Tyler, G. Leonard; Weaver, Harold A.; Woods, Will; New Horizons Science Team

    2016-10-01

    The reconnaissance of the Pluto System by New Horizons in July 2015 included a radio occultation at Pluto. The observation was performed with signals transmitted simultaneously by four antennas of the NASA Deep Space Network, two at the Goldstone complex in California and two at the Canberra complex in Australia. Each antenna radiated 20 kW without modulation at a wavelength of 4.17 cm. New Horizons received the four signals with its 2.1-m high-gain antenna, where the signals were split into pairs and processed independently by two identical REX radio science instruments. Each REX relied on a different ultra-stable oscillator as its frequency reference. The signals were digitized and filtered, and the data samples were stored on the spacecraft for later transmission to Earth. Six months elapsed before all data had arrived on the ground, and the results reported here are the first to utilize the complete set of observations. Pluto's tenuous atmosphere is a significant challenge for radio occultation sounding, which led us to develop a specialized method of analysis. We began by calibrating each signal to remove effects not associated with Pluto's atmosphere, including the diffraction pattern from Pluto's surface. We reduced the noise and increased our sensitivity to the atmosphere by averaging the results from the four signals, while using other combinations of the signals to characterize the noise. We then retrieved profiles of number density, pressure, and temperature from the averaged phase profiles at both occultation entry and exit. Finally, we used a combination of analytical methods and Monte Carlo simulations to determine the accuracy of the measurements. The REX profiles provide the first direct measure of the surface pressure and temperature structure in Pluto's lower atmosphere. There are significant differences between the structure at entry (193.5°E, 17.0°S, sunset) and exit (15.7°E, 15.1°N, sunrise), which arise from spatial variations in surface

  15. Charon's Size And Orbit From Double Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Sicardy, Bruno; Braga-Ribas, F.; Widemann, T.; Jehin, E.; Gillon, M.; Manfroid, J.; Ortiz, J. L.; Morales, N.; Maury, A.; Assafin, M.; Camargo, J. I. B.; Vieira Martins, R.; Dias Oliveira, A.; Ramos Gomes, A., Jr.; Vanzi, L.; Leiva, R.; Young, L. A.; Buie, M. W.; Olkin, C. B.; Young, E. F.; Howell, R. R.; French, R. G.; Bianco, F. B.; Fulton, B. J.; Lister, T. A.; Bode, H. J.; Barnard, B.; Merritt, J. C.; Shoemaker, K.; Vengel, T.; Tholen, D. J.; Hall, T.; Reitsema, H. J.; Wasserman, L. H.; Go, C.

    2012-10-01

    Stellar occultations of a same star by both Pluto and Charon (double events) yield instantaneous relative positions of the two bodies projected in the plane of the sky, at 10km-level accuracy. Assuming a given pole orientation for Charon's orbit, double events provide the satellite plutocentric distance r at a given orbital longitude L (counted from the ascending node on J2000 mean equator), and finally, constraints on its orbit. A double event observed on 22 June 2008 provides r=19,564+/-14 km at L=153.483+/-0.071 deg. (Sicardy et al. 2011), while another double event observed on 4 June 2011 yields: r=19,586+/-15 km at L = 343.211+/-0.072 deg. (all error bars at 1-sigma level). These two positions are consistent with a circular orbit for Charon, with a semi-major axis of a=19,575+\\-10 km. This can be compared to the circular orbit found by Buie et al. (2012), based on Hubble Space Telescope data, with a=19,573+/-2 km. The 4 June 2011 stellar occultation provides 3 chords across Charon, from which a radius of Rc= 602.4+/-1.6 km is derived. This value can be compared to that obtained from the 11 July 2005 occultation: Rc= 606.0+/-1.5 km (Person et al. 2006) and Rc= 603.6+/-1.4 km (Sicardy et al. 2006). A third double event, observed on 23 June 2011 is under ongoing analysis, and will be presented. Buie et al. (2012), AJ 144, 15-34 (2012) Person et al, AJ 132, 1575-1580 (2006) Sicardy et al., Nature 439, 52-54 (2006) Sicardy et al., AJ 141, 67-83 (2011) B.S. thanks ANR "Beyond Neptune II". L.A.Y. acknowledges support by NASA, New Horizons and National Geographic grants. We thank B. Barnard, M.J. Brucker, J. Daily, C. Erikson, W. Fukunaga, C. Harlinten, C. Livermore, C. Nance, J.R. Regester, L. Salas, P. Tamblyn, R. Westhoff for help in the observations.

  16. A case of occult contralateral breast cancer incidentally detected by contrast-enhanced MRI; report of a case with review of literature.

    PubMed

    Komatsu, Shuhei; Lee, Chol Joo; Hosokawa, Yohei; Hamashima, Takashi; Shirono, Koichi; Ichikawa, Daisuke; Okabe, Harumi; Kurioka, Hideaki; Yamagishi, Hisakazu; Oka, Takahiro

    2005-01-01

    We encountered a case of occult contralateral breast cancer, previously undetected by conventional imaging such as mammography (MMG) and ultrasonography (US), but incidentally detected by contrast-enhanced magnetic resonance imaging (CE-MRI). We present it here with a review of the literature. A 67-year-old Japanese woman was referred to our hospital in October 2000 because of a 1.5 cm right breast lump detected in a medical checkup. MMG, US and fine needle aspiration cytology revealed a cancerous lesion during the right breast. No mass lesion was palpable nor was any detected by MMG or US in the left breast. Bilateral breast CE-MRI was performed for more detailed evaluation. Consequently, an occult contralateral breast cancerous lesion was detected incidentally by CE-MRI, with the images showing rapid initial enhancement of time to signal intensity curves. Before surgery, bilateral breast lesions were diagnosed as invasive ductal carcinoma by open biopsy. She underwent bilateral breast conserving surgery with bilateral axillary lymph node dissection. The postoperative course was uneventful and no recurrence has been noted as of January 18th, 2004. CE-MRI of the contralateral breast should be of value as a routine screen in those patients with a known or suspected malignancy in one breast considering the limits of breast cancer detection by such conventional modalities as MMG and US. PMID:16286918

  17. Resolving dynamic parameters of the August 2007 Titania and Ariel occultations by Umbriel

    NASA Astrophysics Data System (ADS)

    Miller, C.; Chanover, N. J.

    2009-03-01

    We observed the 15 August 2007 occultation of the uranian satellite Titania and the 19 August 2007 occultation of Ariel by Umbriel using the Agile high-speed photometer on the APO 3.5 m telescope. We find that the Titania event midpoint occurred at 09:16:39.20 UT and the Ariel event midpoint at 07:59:49.4 UT, which was 26.2 s and 37.4 s later than predicted, respectively. Our best fit impact parameter was 71.0 km for the Titania occultation and 476.9 km for the Ariel event, both of which were less than predicted.

  18. Heparin as a pharmacologic intervention to induce positive scintiscan in occult gastrointestinal bleeding

    SciTech Connect

    Chaudhuri, T.K.; Brantly, M.

    1984-04-01

    The value of using heparin as a pharmacologic intervention to induce a positive scintiscan was studied in a patient with chronic occult gastrointestinal bleeding. When all standard diagnostic tests (upper and lower gastrointestinal series, upper and lower endoscopy, and conventional noninterventional Tc-99m RBC imaging) fail to detect and localize gastrointestinal bleeding in a patient who has definite clinical evidence (guaiac positive stool and dropping hemoglobin, hematocrit) of chronic occult gastrointestinal oozing, heparin may be used (with proper precaution) as a last resort to aid in the scintigraphic detection and localization of chronic occult gastrointestinal bleeding.

  19. Stellar occultation candidates from the guide star catalog. I - Saturn, 1991-1999

    NASA Technical Reports Server (NTRS)

    Bosh, A. S.; Mcdonald, S. W.

    1992-01-01

    A list of 203 potential occultations by Saturn and its ring of stars from the HST Guide Star Catalog (GSC) during the years 1991-1999 is presented. This list features many fainter candidates than do current occultation candidate lists for Saturn; these fainter stars can also provide a high signal-to-noise ratio if observed with a large telescope or in the IR where Saturn and its rings have absorption bands. The occultation circumstances are listed, as well as star information found in the GSC.

  20. Recovery of atmospheric parameters from the Apollo/Soyuz-ATS-F radio occultation data

    NASA Technical Reports Server (NTRS)

    Rangaswamy, S.

    1976-01-01

    As part of the Apollo-Soyuz Test Project, Apollo was tracked in the satellite-to-satellite tracking mode by ATS-F. The tracking data obtained at occultation of Apollo by the earth has been used in this study to compute atmospheric parameters like pressure and temperature. The results of the numerical inversion have been compared with data from a radiosonde station near the occultation site. Near the surface of the earth, the refractivity computed from occultation data agreed with the radiosonde-derived values to within 3%. A pressure profile deduced from the refractivity profile by using a simplified model of the atmosphere showed good agreement with radiosonde measurements.

  1. Response to antiretroviral therapy in occult hepatitis B and HIV co-infection in West Africa.

    PubMed

    Chadwick, David; Stanley, Alastair; Sarfo, Stephen; Appiah, Lambert; Ankcorn, Michael; Foster, Geraldine; Schwab, Uli; Phillips, Richard; Geretti, Anna M

    2013-01-01

    This study evaluated the outcome of first-line antiretroviral therapy among 35 Ghanaians with occult HBV/HIV co-infection, comparing them over 2 years to 120 patients with HBsAg+ HBV/HIV co-infection and 230 patients without HBV co-infection. Increases in CD4 cell count and BMI were similar, whereas elevations of hepatic transaminases were more frequent in both the occult HBV and HBsAg+ patients. Occult HBV/HIV co-infection appears not to impact adversely on response to antiretroviral therapy in Ghana. PMID:22874516

  2. The photometric search for earth-sized extrasolar planets by occultation in binary systems

    NASA Astrophysics Data System (ADS)

    Schneider, J.; Chevreton, M.

    1990-06-01

    The feasibility of the detection of small extrasolar planets by the partial occultation they can cause on eclipsing binaries is investigated. This study is applied to the eight most luminous systems; the probability that an occultation can occur is estimated. It is found that the continuous observation of these eight objects would give a high probability of detecting at least one planet if they all have planetary companions. The uncertainty that can be expected on the period of revolution of the planet from a single occultation observation is discussed.

  3. Calorie intake, olive oil consumption and mammographic density among Spanish women

    PubMed Central

    García-Arenzana, Nicolás; Navarrete-Muñoz, Eva María; Lope, Virginia; Moreo, Pilar; Vidal, Carmen; Laso-Pablos, Soledad; Ascunce, Nieves; Casanova-Gómez, Francisco; Sánchez-Contador, Carmen; Santamariña, Carmen; Aragonés, Nuria; Gómez, Beatriz Pérez; Vioque, Jesús; Pollán, Marina

    2014-01-01

    High mammographic density (MD) is one of the main risk factors for development of breast cancer. To date, however, relatively few studies have evaluated the association between MD and diet. In this cross-sectional study, we assessed the association between MD (measured using Boyd's semiquantitative scale with five categories: <10%, 10–25%, 25–50%, 50–75% and >75%) and diet (measured using a food frequency questionnaire validated in a Spanish population) among 3,548 peri- and postmenopausal women drawn from seven breast cancer screening programs in Spain. Multivariate ordinal logistic regression models, adjusted for age, body mass index (BMI), energy intake and protein consumption as well as other confounders, showed an association between greater calorie intake and greater MD [odds ratio (OR) = 1.23; 95% confidence interval (CI) = 1.10-1.38, for every increase of 500 cal/day], yet high consumption of olive oil was nevertheless found to reduce the prevalence of high MD (OR = 0.86;95% CI = 0.76-0.96, for every increase of 22 g/day in olive oil consumption); and, while greater intake of whole milk was likewise associated with higher MD (OR = 1.10; 95%CI 1.00-1.20, for every increase of 200 g/day), higher consumption of protein (OR = 0.89; 95% CI 0.80-1.00, for every increase of 30 g/day) and white meat (p for trend 0.041) was found to be inversely associated with MD. Our study, the largest to date to assess the association between diet and MD, suggests that MD is associated with modifiable dietary factors, such as calorie intake and olive oil consumption. These foods could thus modulate the prevalence of high MD, and important risk marker for breast cancer. PMID:24254818

  4. Body size throughout the life course and mammographic density in Mexican women

    PubMed Central

    Rice, Megan S.; Bertrand, Kimberly A.; Lajous, Martin; Tamimi, Rulla M.; Torres-Mejía, Gabriela; Biessy, Carine; López-Ridaura, Ruy; Romieu, Isabelle

    2013-01-01

    Mammographic density (MD) is a strong risk factor for breast cancer, but the biological mechanism underlying this association is not clear. Current adult body mass index (BMI) is inversely associated with percent MD; however, few studies have included Hispanic women or evaluated associations with measures of body fatness earlier in life. ESMaestras was established in 2006, when 28,345 women ages ≥35 responded to a detailed questionnaire that assessed possible disease risk factors, including body fatness in childhood, adolescence, and young adulthood. In 2007, 2,084 ESMaestras participants underwent a clinical examination, which included measurements of weight, height, and sitting height and a mammogram. We measured percent MD using a computer-assisted method. The current analysis includes 972 premenopausal and 559 postmenopausal women. We used multivariable linear regression to evaluate associations between measures of body size and MD, independent of current BMI. Among pre- and postmenopausal women, we observed no significant associations between body fatness during childhood, adolescence or young adulthood and percent MD. Among postmenopausal women, we observed a modest positive association between body fatness immediately before first pregnancy and between ages 25–35 after adjustment for current BMI, with differences of 4.9 and 3.6 percentage points, respectively, in percent MD between the heaviest and leanest women (p-trend = 0.02). There were no significant associations between height, sitting height, and percent MD among pre- or postmenopausal women in multivariable models adjusting for BMI. In general, we found no clear associations between measures of body size in early life, current sitting height, or current height, and percent MD, after adjusting for current BMI, in this population of Mexican women. Our observation of a positive association between early adult body fatness (i.e., before first pregnancy and ages 25–35) and percent MD among

  5. American College of Radiology Imaging Network digital mammographic imaging screening trial: objectives and methodology.

    PubMed

    Pisano, Etta D; Gatsonis, Constantine A; Yaffe, Martin J; Hendrick, R Edward; Tosteson, Anna N A; Fryback, Dennis G; Bassett, Lawrence W; Baum, Janet K; Conant, Emily F; Jong, Roberta A; Rebner, Murray; D'Orsi, Carl J

    2005-08-01

    This study was approved by the Institutional Review Board (IRB) of the American College of Radiology Imaging Network (ACRIN) and each participating site and by the IRB and the Cancer Therapy Evaluation Program at the National Cancer Institute. The study was monitored by an independent Data Safety and Monitoring Board, which received interim analyses of data to ensure that the study would be terminated early if indicated by trends in the outcomes. The ACRIN, which is funded by the National Cancer Institute, conducted the Digital Mammographic Imaging Screening Trial (DMIST) primarily to compare the diagnostic accuracy of digital and screen-film mammography in asymptomatic women presenting for screening for breast cancer. Over the 25.5 months of enrollment, a total of 49 528 women were included at the 33 participating sites, which used five different types of digital mammography equipment. All participants underwent both screen-film and digital mammography. The digital and screen-film mammograms of each subject were independently interpreted by two radiologists. If findings of either examination were interpreted as abnormal, subsequent work-up occurred according to the recommendations of the interpreting radiologist. Breast cancer status was determined at biopsy or follow-up mammography 11-15 months after study entry. In addition to the measurement of diagnostic accuracy by using the interpretations of mammograms at the study sites, DMIST included evaluations of the relative cost-effectiveness and quality-of-life effects of digital versus screen-film mammography. Six separate reader studies using the de-identified archived DMIST mammograms will also assess the diagnostic accuracy of each of the individual digital mammography machines versus screen-film mammography machines, the effect of breast density on diagnostic accuracy of digital and screen-film mammography, and the effect of different rates of breast cancer on the diagnostic accuracy in a reader study. PMID

  6. Clinical comparison of a novel breast DXA technique to mammographic density

    SciTech Connect

    Shepherd, John A.; Herve, Lionel; Landau, Jessie; Fan Bo; Kerlikowske, Karla; Cummings, Steve R.

    2006-05-15

    We compare mammography breast density (BD{sub MD}) to the measure of breast composition using a clinical dual energy absorptiometry (DXA) system (BD{sub DXA}) calibrated to measure breast density. A DXA scanning protocol was developed to scan breasts isolated in the DXA scan field in either a prone pendulous or decubitus mediolateral position. A total of 17 participants were recruited among women undergoing clinical mammography examinations. Each participant had duplicate DXA scans and duplicate craniocaudal-view mammograms of their right breast with repositioning between each scan and one DXA and one craniocaudal-view mammogram of their left breast. The in vivo repeatability (RMS SD) of BD{sub DXA} and BD{sub MD} on duplicate scans was found to be 1.2% for BD{sub DXA} and 1.4% for BD{sub MD} when repeat BD{sub MD} measures were made on the same day. When repeat BD{sub MD} measures of the same breast were made more than 50 days apart, the repeatability decreased to 5.5%. Left and right breast measurements were highly correlated with both techniques at r{sup 2}=0.98 for BD{sub DXA} and r{sup 2}=0.86 for BD{sub MD}. Moderate correlation (r{sup 2}=0.52) was found between BD{sub DXA} and BD{sub MD} measurements. However, after recalibrating the DXA system to mammography reference materials, negative percent fibroglandular values were measured for the most fatty breasts. Thus, our results are reproducible and accurate to common mammography tissue standards, but did not accurately reflect true percent fibroglandular levels and further development of phantom standards are necessary. We conclude that breast composition can be precisely evaluated and assessed with clinical DXA densitometers at a lower dose than with mammographic breast density methods.

  7. Quantitative estimates of the impact of sensitivity and specificity in mammographic screening in Germany.

    PubMed Central

    Warmerdam, P G; de Koning, H J; Boer, R; Beemsterboer, P M; Dierks, M L; Swart, E; Robra, B P

    1997-01-01

    STUDY OBJECTIVE: To estimate quantitatively the impact of the quality of mammographic screening (in terms of sensitivity and specificity) on the effects and costs of nationwide breast cancer screening. DESIGN: Three plausible "quality" scenarios for a biennial breast cancer screening programme for women aged 50-69 in Germany were analysed in terms of costs and effects using the Microsimulation Screening Analysis model on breast cancer screening and the natural history of breast cancer. Firstly, sensitivity and specificity in the expected situation (or "baseline" scenario) were estimated from a model based analysis of empirical data from 35,000 screening examinations in two German pilot projects. In the second "high quality" scenario, these properties were based on the more favourable diagnostic results from breast cancer screening projects and the nationwide programme in The Netherlands. Thirdly, a worst case, "low quality" hypothetical scenario with a 25% lower sensitivity than that experienced in The Netherlands was analysed. SETTING: The epidemiological and social situation in Germany in relation to mass screening for breast cancer. RESULTS: In the "baseline" scenario, an 11% reduction in breast cancer mortality was expected in the total German female population, ie 2100 breast cancer deaths would be prevented per year. It was estimated that the "high quality" scenario, based on Dutch experience, would lead to the prevention of an additional 200 deaths per year and would also cut the number of false positive biopsy results by half. The cost per life year gained varied from Deutsche mark (DM) 15,000 on the "high quality" scenario to DM 21,000 in the "low quality" setting. CONCLUSIONS: Up to 20% of the total costs of a screening programme can be spent on quality improvement in order to achieve a substantially higher reduction in mortality and reduce undesirable side effects while retaining the same cost effectiveness ratio as that estimated from the German data

  8. Vision 20/20: Mammographic breast density and its clinical applications

    SciTech Connect

    Ng, Kwan-Hoong Lau, Susie

    2015-12-15

    Breast density is a strong predictor of the failure of mammography screening to detect breast cancer and is a strong predictor of the risk of developing breast cancer. The many imaging options that are now available for imaging dense breasts show great promise, but there is still the question of determining which women are “dense” and what imaging modality is suitable for individual women. To date, mammographic breast density has been classified according to the Breast Imaging-Reporting and Data System (BI-RADS) categories from visual assessment, but this is known to be very subjective. Despite many research reports, the authors believe there has been a lack of physics-led and evidence-based arguments about what breast density actually is, how it should be measured, and how it should be used. In this paper, the authors attempt to start correcting this situation by reviewing the history of breast density research and the debates generated by the advocacy movement. The authors review the development of breast density estimation from pattern analysis to area-based analysis, and the current automated volumetric breast density (VBD) analysis. This is followed by a discussion on seeking the ground truth of VBD and mapping volumetric methods to BI-RADS density categories. The authors expect great improvement in VBD measurements that will satisfy the needs of radiologists, epidemiologists, surgeons, and physicists. The authors believe that they are now witnessing a paradigm shift toward personalized breast screening, which is going to see many more cancers being detected early, with the use of automated density measurement tools as an important component.

  9. Longitudinal Change in Mammographic Density among ER-Positive Breast Cancer Patients Using Tamoxifen.

    PubMed

    Nyante, Sarah J; Sherman, Mark E; Pfeiffer, Ruth M; Berrington de Gonzalez, Amy; Brinton, Louise A; Bowles, Erin J Aiello; Hoover, Robert N; Glass, Andrew; Gierach, Gretchen L

    2016-01-01

    Tamoxifen-associated mammographic density (MD) reductions are linked to improved breast cancer survival. We evaluated MD at six time points to determine the timing of greatest reduction following tamoxifen initiation. We sampled 40 Kaiser Permanente Northwest estrogen receptor (ER)-positive breast cancer patients from a prior study of MD change, according to tamoxifen use duration and age at diagnosis: <4 years tamoxifen and ≤50 years (N = 6) or >50 years (N = 10) old; ≥4 years tamoxifen and ≤50 years (N = 13) or >50 years (N = 11) old. A single reader evaluated percent MD in the contralateral breast on baseline (pre-diagnosis) and five approximately yearly post-diagnostic (T1 to T5) mammograms. Mean MD change was calculated. Interactions with age (≤50 and >50 years), tamoxifen duration (<4 and ≥4 years), and baseline MD (tertiles) were tested in linear regression models. Overall, the largest MD decline occurred by T1 (mean 4.5%) with little additional decline by T5. Declines differed by tertile of baseline MD (Pinteraction < 0.01). In the highest tertile, the largest reduction occurred by T1 (mean 14.9%), with an additional reduction of 3.6% by T5. Changes were smaller in the middle and lowest baseline MD tertiles, with cumulative reductions of 3.0% and 0.4% from baseline to T5, respectively. There were no differences by age (Pinteraction = 0.36) or tamoxifen duration (Pinteraction = 0.42). Among ER-positive patients treated with tamoxifen and surviving ≥5 years, most of the MD reduction occurred within approximately 12 months of tamoxifen initiation, suggesting that MD measurement at a single time point following tamoxifen initiation can identify patients with substantial density declines. PMID:26545407

  10. Signal analysis and radioholographic methods for airborne radio occultations

    NASA Astrophysics Data System (ADS)

    Wang, Kuo-Nung

    Global Positioning System (GPS) radio occultation (RO) is an atmospheric sounding technique utilizing the change in propagation direction and delay of the GPS signal to measure refractivity, which provides information on temperature and humidity. The GPS-RO technique is now operational on several Low Earth Orbiting (LEO) satellite missions. Nevertheless, when observing localized transient events, such as tropical storms, current LEO satellite systems cannot provide sufficiently high temporal and spatial resolution soundings. An airborne RO (ARO) system has therefore been developed for localized GPS-RO campaigns. The open-loop (OL) tracking in post-processing is used to cross-correlates the received Global Navigation Satellite System (GNSS) signal with an internally generated local carrier signal predicted from a Doppler model and extract the atmospheric refractivity information. OL tracking also allows robust processing of rising GPS signals using backward tracking, which will double the observed occultation event numbers. RO signals in the lower troposphere are adversely affected by rapid phase accelerations and severe signal power fading, however. The negative bias caused by low signal-to-noise ratio (SNR) and multipath ray propagation limits the depth of tracking in the atmosphere. Therefore, we developed a model relating the SNR to the variance in the residual phase of the observed signal produced from OL tracking, and its applicability to airborne data is demonstrated. We then apply this model to set a threshold on refractivity retrieval, based upon the cumulative unwrapping error bias, to determine the altitude limit for reliable signal tracking. To enhance the SNR and decrease the unwrapping error rate, the CIRA-Q climatological model and signal residual phase pre-filtering are utilized to process the ARO residual phase. This more accurately modeled phase and less noisy received signal are shown to greatly reduce the bias caused by unwrapping error at lower

  11. Atmospheric constituent density profiles from full disk solar occultation experiments

    NASA Technical Reports Server (NTRS)

    Lumpe, J. D.; Chang, C. S.; Strickland, D. J.

    1991-01-01

    Mathematical methods are described which permit the derivation of the number of density profiles of atmospheric constituents from solar occultation measurements. The algorithm is first applied to measurements corresponding to an arbitrary solar-intensity distribution to calculate the normalized absorption profile. The application of Fourier transform to the integral equation yields a precise expression for the corresponding number density, and the solution is employed with the data given in the form of Laguerre polynomials. The algorithm is employed to calculate the results for the case of uniform distribution of solar intensity, and the results demonstrate the convergence properties of the method. The algorithm can be used to effectively model representative model-density profiles with constant and altitude-dependent scale heights.

  12. Exploring overstabilities in Saturn's a ring using two stellar occultations

    SciTech Connect

    Hedman, M. M.; Nicholson, P. D.; Salo, H.

    2014-07-01

    Certain regions of Saturn's rings exhibit periodic opacity variations with characteristic radial wavelengths of up to a few hundred meters that have been attributed to viscous overstabilities. The Visual and Infrared Mapping Spectrometer on board the Cassini spacecraft observed two stellar occultations of the star γ Crucis that had sufficient resolution to discern a subset of these periodic patterns in a portion of the A ring between 124,000 and 125,000 km from Saturn's center. These data reveal that the wavelengths and intensities of the patterns vary systematically across this region, but that these parameters are not strictly determined by the ring's average optical depth. Furthermore, our observations indicate that these opacity variations have an azimuthal coherence scale of around 3000 km.

  13. Modeling and analysis of pinhole occulter experiment: Initial study phase

    NASA Technical Reports Server (NTRS)

    Vandervoort, R. J.

    1985-01-01

    The feasibility of using a generic simulation, TREETOPS, to simulate the Pinhole/Occulter Facility (P/OF) to be tested on the space shuttle was demonstrated. The baseline control system was used to determine the pointing performance of the P/OF. The task included modeling the structure as a three body problem (shuttle-instrument pointing system- P/OP) including the flexibility of the 32 meter P/OF boom. Modeling of sensors, actuators, and control algorithms was also required. Detailed mathematical models for the structure, sensors, and actuators are presented, as well as the control algorithm and corresponding design procedure. Closed loop performance using this controller and computer listings for the simulator are also given.

  14. Radiosensitive orbital metastasis as presentation of occult colonic adenocarcinoma

    PubMed Central

    Ludmir, Ethan B; McCall, Shannon J; Czito, Brian G; Palta, Manisha

    2014-01-01

    An 82-year-old man presented with progressive right frontal headaches. The patient's history was significant for benign polyps on surveillance colonoscopy 2 years prior, without high-grade dysplasia or carcinoma. MRI revealed an enhancing lesion arising within the superomedial aspect of the right orbit. Lesion biopsy demonstrated histological appearance and immunophenotype suggestive of colonic adenocarcinoma. Staging positron emission tomography/CT showed visceral metastases and diffuse activity in the posterior rectosigmoid, consistent with metastatic colon cancer. Treatment of the orbital lesion with external beam radiotherapy to 30 Gy resulted in significant palliation of the patient's headaches. The patient expired 2 months following treatment completion due to disease progression. Orbital metastasis as the initial presentation of an occult colorectal primary lesion is exceedingly rare, and occurred in this patient despite surveillance colonoscopy. Radiotherapy remains an efficacious modality for treatment of orbital metastases. PMID:25240005

  15. Data inversion algorithm development for the hologen occultation experiment

    NASA Technical Reports Server (NTRS)

    Gordley, Larry L.; Mlynczak, Martin G.

    1986-01-01

    The successful retrieval of atmospheric parameters from radiometric measurement requires not only the ability to do ideal radiometric calculations, but also a detailed understanding of instrument characteristics. Therefore a considerable amount of time was spent in instrument characterization in the form of test data analysis and mathematical formulation. Analyses of solar-to-reference interference (electrical cross-talk), detector nonuniformity, instrument balance error, electronic filter time-constants and noise character were conducted. A second area of effort was the development of techniques for the ideal radiometric calculations required for the Halogen Occultation Experiment (HALOE) data reduction. The computer code for these calculations must be extremely complex and fast. A scheme for meeting these requirements was defined and the algorithms needed form implementation are currently under development. A third area of work included consulting on the implementation of the Emissivity Growth Approximation (EGA) method of absorption calculation into a HALOE broadband radiometer channel retrieval algorithm.

  16. Occult pulmonary embolism: a common occurrence in deep venous thrombosis

    SciTech Connect

    Dorfman, G.S.; Cronan, J.J.; Tupper, T.B.; Messersmith, R.N.; Denny, D.F.; Lee, C.H.

    1987-02-01

    Ventilation-perfusion scans were used in a prospective study to determine the prevalence of occult pulmonary embolus in proven deep venous thrombosis. Fifty-eight patients without symptoms of pulmonary embolism, but with venographically proven deep venous thrombosis, were subjected to chest radiographs, /sup 99m/Tc macroaggregated-albumin perfusion scans, and /sup 133/Xe ventilation scans. Of the 49 patients with deep venous thrombosis proximal to the calf veins, 17 (35%) had high-probability scans. Of all 58 patients, only 12 (21%) had normal scans. When the study population was compared with a group of 430 patients described in reports of pulmonary perfusion in asymptomatic persons, a significantly higher percentage of high-probability scans was found in the study population with deep venous thrombosis. Baseline ventilation-perfusion lung scanning is valuable for patients with proven above-knee deep venous thrombosis.

  17. Occult purulent pericarditis detected by indium-111 leukocyte imaging

    SciTech Connect

    Greenberg, M.L.; Niebulski, H.I.; Uretsky, B.F.; Salerni, R.; Klein, H.A.; Forstate, W.J.; Starzl, T.E.

    1984-05-01

    Leukocyte imaging with indium-111 is a relatively new technique which, to this point in time, has been discussed almost exclusively in the radiologic literature. Although this procedure has been used mainly to detect intra-abdominal infection, the thorax is routinely imaged along with the abdomen, and therefore detection of cardiac disease may be feasible. This case report is of a young woman after liver transplantation who developed occult purulent pericarditis initially detected by a leukocyte scan with indium-111. This case demonstrates that striking pericardial uptake on a whole-body indium-111 leukocyte scan can occur with purulent pericarditis, and it reemphasizes how insidiously purulent pericarditis may present in an immunosuppressed patient.

  18. An overview of the halogen occultation experiment (HALOE)

    NASA Technical Reports Server (NTRS)

    Russell, James M., III

    1991-01-01

    The HALOE experiment will fly on the Upper Atmosphere Research Satellite (UARS) in the last quarter of 1991. The experiment uses the solar occultation limb sounding approach, in combination with gas filter and broadband radiometry to provide measurements of temperature profiles and key gases in the ClO(y), NO(y), and HO(y) chemical families of the middle atmosphere. The instrument has been characterized in great detail to determine gains, spectral response, noise, crosstalk, field-of-view, and thermal drift characteristics. A final end-to-end test using a gas cell to simulate the atmosphere demonstrated measurement repeatability to about 1 percent and agreement between measured and calculated signals to within about 1 percent to 3 percent. This latter agreement provides confidence in knowledge of both the hardware as well as the software.

  19. Sun sensor boresight alignment testing for the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Moore, A. S.; Laney, V. S.; Mauldin, L. E., III

    1987-01-01

    The boresight alignment testing for the sun sensor assembly on the Halogen Occultation Experiment (HALOE) is described. The sun sensor assembly consists of three sensors that provide feedback signals for controlling dual axes gimbals. Two energy balancing silicon detectors are operated as wideband sensors in the azimuth and elevation axes. The third sensor is a silicon photodiode array operated as a narrow-band sensor in the elevation axis. These sensors are mounted on a common Invar structure which is mounted to the HALOE telescope. A blackbody was used as the stimulating source to perform the initial boresight alignment and this was checked with a heliostat solar look and a direct solar look. These tests are explained with a comparison between each source used.

  20. Occult Pneumomediastinum in the Deployed Setting: Evaluation and Management.

    PubMed

    Reha, Jeffrey; Davis, Patrick

    2016-08-01

    Pneumomediastinum can occur after both blunt and penetrating trauma. The greatest concern involving this finding in a trauma patient is an aerodigestive tract injury. Prompt evaluation, identification, and management of these injuries are extremely important. This case describes a soldier who was involved in an improvised explosive device blast with no evidence of cavity penetration. During the routine evaluation of his head and neck an occult pneumomediastinum was identified. The patient was asymptomatic and was further evaluated with computed tomography because of the absence of endoscopy and bronchoscopy in theatre. The imaging showed no evidence of esophageal or tracheobronchial injury. The patient was observed and when noted to be stable was transferred to the local Role 3 hospital for management of his other injuries. PMID:27483543

  1. HITRAN spectroscopy evaluation using solar occultation FTIR spectra

    NASA Astrophysics Data System (ADS)

    Toon, Geoffrey C.; Blavier, Jean-Francois; Sung, Keeyoon; Rothman, Laurence S.; E. Gordon, Iouli

    2016-10-01

    High resolution FTIR solar occultation spectra, acquired by the JPL MkIV Fourier transform spectrometer from balloon, covering 650-5650 cm-1 at 0.01 cm-1 resolution, are systematically analyzed using the last four versions of the HITRAN linelist (2000, 2004, 2008, 2012). The rms spectral fitting residuals are used to assess the quality and adequacy of the linelists as a function of wavenumber and altitude. Although there have been substantial overall improvements with each successive version of HITRAN, there are nevertheless a few spectral regions where the latest HITRAN version (2012) has regressed, or produces residuals that far exceed the noise level. A few of these instances are investigated further and their causes identified. We emphasize that fitting atmospheric spectra, in addition to laboratory spectra, should be part of the quality assurance for any new linelist before public release.

  2. External occulters for direct observation of exoplanets: an overview

    NASA Astrophysics Data System (ADS)

    Cash, W.; Schindhelm, E.; Arenberg, J.; Lo, A.; Polidan, R.; Kasdin, J.; Vanderbei, R.; Kilston, S.; Noecker, C.

    2007-09-01

    Perhaps the most compelling piece of science and exploration now under discussion for future space missions is the direct study of planets circling other stars. Indirect means have established planets as common in the universe but have given us a limited view of their actual characteristics. Direct observation holds the potential to map entire planetary systems, view newly forming planets, find Earth-like planets and perform photometry to search for major surface features. Direct observations will also enable spectroscopy of exoplanets and the search for evidence of simple life in the universe. Recent advances in the design of external occulters - starshades that block the light from the star while passing exoplanet light - have lowered their cost and improved their performance to the point where we can now envision a New Worlds Observer that is both buildable and affordable with today's technology. We will summarize recent studies of such missions and show they provide a very attractive alternative near term mission.

  3. Genetic variation of occult hepatitis B virus infection

    PubMed Central

    Zhu, Hui-Lan; Li, Xu; Li, Jun; Zhang, Zhen-Hua

    2016-01-01

    Occult hepatitis B virus infection (OBI), characterized as the persistence of hepatitis B virus (HBV) surface antigen (HBsAg) seronegativity and low viral load in blood or liver, is a special form of HBV infection. OBI may be related mainly to mutations in the HBV genome, although the underlying mechanism of it remains to be clarified. Mutations especially within the immunodominant “α” determinant of S protein are “hot spots” that could contribute to the occurrence of OBI via affecting antigenicity and immunogenicity of HBsAg or replication and secretion of virion. Clinical reports account for a large proportion of previous studies on OBI, while functional analyses, especially those based on full-length HBV genome, are rare. PMID:27053845

  4. Glioma coexisting with angiographically occult cerebrovascular malformation: A case report

    PubMed Central

    Chen, Junhui; Chen, Lei; Zhang, Chunlei; He, Jianqing; Li, Peipei; Zhou, Jingxu; Zhu, Jun; Wang, Yuhai

    2016-01-01

    Angiographically occult cerebrovascular malformation (AOVM) is a type of complex cerebrovascular malformation that is not visible on digital subtraction angiography (DSA). Vascular malformation coexisting with glioma is clinically rare, and glioma coexisting with AOVM is even more rare. To the best of our knowledge, the present study is the first to report glioma coexisting with AOVM in the literature. The present study reports a rare case of glioma coexisting with AOVM in a 30-year-old male patient. Computed tomography (CT) scan revealed calcification, hemorrhage and edema in the right frontal lobe. CT angiography revealed a vascular malformation in the right frontal lobe, which was not observed on DSA. Finally, glioma coexisting with AOVM was confirmed by 2.0T magnetic resonance imaging and postoperative pathological examination. The present patient had a positive outcome and no neurological dysfunctions during the 6-month follow-up subsequent to surgery. PMID:27698825

  5. Second-stage acceleration in a limb-occulted flare

    NASA Technical Reports Server (NTRS)

    Hudson, H. S.; Lin, R. P.; Stewart, R. T.

    1982-01-01

    From radio observations it is known that two distinct groups of phenomena occur in large solar flares. The phenomena are related to an impulsive phase of approximately 100 s duration in the early stage of a flare and a following second phase lasting for tens of minutes. A study is presented of the limb-occulted flare event of July 22, 1972, giving particular attention to the second stage particle acceleration. The study takes into account hard X-ray, energetic particle, and radio observations. The conducted analysis shows that second stage acceleration is physically distinct from the impulsive phase, and is characterized by continuous and widespread electron acceleration to high energies, most likely by the type II burst shock wave.

  6. Cloud identification in atmospheric trace molecule spectroscopy infrared occultation measurements.

    PubMed

    Kahn, Brian H; Eldering, Annmarie; Irion, Fredrick W; Mills, Franklin P; Sen, Bhaswar; Gunson, Michael R

    2002-05-20

    High-resolution infrared nongas absorption spectra derived from the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment are analyzed for evidence of the presence of cirrus clouds. Several nonspherical ice extinction models based on realistic size distributions and crystal habits along with a stratospheric sulfate aerosol model are fit to the spectra, and comparisons are made with different model combinations. Nonspherical ice models often fit observed transmission spectra better than a spherical Mie ice model, and some discrimination among nonspherical models is noted. The ATMOS lines of sight for eight occultations are superimposed on coincident geostationary satellite infrared imagery, and brightness temperatures along the lines of sight are compared with retrieved vertical temperature profiles. With these comparisons, studies of two cases of clear sky, three cases of opaque cirrus, and three cases of patchy cirrus are discussed.

  7. Remote sensing of tropospheric turbulence using GPS radio occultation

    NASA Astrophysics Data System (ADS)

    Shume, Esayas; Ao, Chi

    2016-07-01

    Radio occultation (RO) measurements are sensitive to the small-scale irregularities in the atmosphere. In this study, we present a new technique to estimate tropospheric turbulence strength (namely, scintillation index) by analyzing RO amplitude fluctuations in impact parameter domain. GPS RO observations from the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) satellites enabled us to calculate global maps of scintillation measures, revealing the seasonal, latitudinal, and longitudinal characteristics of the turbulent troposphere. Such information are both difficult and expensive to obtain especially over the oceans. To verify our approach, simulation experiments using the multiple phase screen (MPS) method were conducted. The results show that scintillation indices inferred from the MPS simulations are in good agreement with scintillation measures estimated from COSMIC observations.

  8. Remote Sensing of Tropospheric Turbulence Using GPS Radio Occultation

    NASA Astrophysics Data System (ADS)

    Shume, E. B.; Ao, C. O.

    2015-12-01

    The purposes of this abstract are twofold: (i) It presents estimates of tropospheric turbulence strength (namely, scintillation index) by analyzing radio occultation (RO) observations from the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) satellites. The availability of global observation worth of several years of COSIMC RO profiles enabled us to calculate global maps of scintillation measures (such information are both difficult and expensive especially over the oceans) revealing the seasonal, latitudinal, and longitudinal characteristics of the turbulent troposphere in greater details, and (ii) the manuscript also presents the application of a multiple phase screen (MPS) model simulation to investigate and quantify the effects of tropospheric turbulence on L-band communication and navigation signals received in a GPS (Global Positioning System) to a LEO (Low Earth Orbiting) satellites radio links. The scintillation indices inferred from the MPS simulations are shown to be in a reasonable agreement with scintillation measures estimated from COSMIC RO observations.

  9. Glioma coexisting with angiographically occult cerebrovascular malformation: A case report

    PubMed Central

    Chen, Junhui; Chen, Lei; Zhang, Chunlei; He, Jianqing; Li, Peipei; Zhou, Jingxu; Zhu, Jun; Wang, Yuhai

    2016-01-01

    Angiographically occult cerebrovascular malformation (AOVM) is a type of complex cerebrovascular malformation that is not visible on digital subtraction angiography (DSA). Vascular malformation coexisting with glioma is clinically rare, and glioma coexisting with AOVM is even more rare. To the best of our knowledge, the present study is the first to report glioma coexisting with AOVM in the literature. The present study reports a rare case of glioma coexisting with AOVM in a 30-year-old male patient. Computed tomography (CT) scan revealed calcification, hemorrhage and edema in the right frontal lobe. CT angiography revealed a vascular malformation in the right frontal lobe, which was not observed on DSA. Finally, glioma coexisting with AOVM was confirmed by 2.0T magnetic resonance imaging and postoperative pathological examination. The present patient had a positive outcome and no neurological dysfunctions during the 6-month follow-up subsequent to surgery.

  10. Occultation determination of Neptune's oblateness and stratospheric methane mixing ratio

    NASA Technical Reports Server (NTRS)

    Lellouch, E.; Hubbard, W. B.; Sicardy, B.; Vilas, F.; Bouchet, P.

    1986-01-01

    The occultation of a star by Neptune on August 20, 1985 was observed at 2.2 micron wavelength with telescopes at the European Southern Observatory (ESO) and the Cerro Tololo Inter-American Observatory (CTIO). The detection of a 'central flash' midway between immersion and emersion has allowed the determination of Neptune's oblateness and the atmospheric extinction at 2.2 microns, which is related to the stratospheric methane mixing ratio. An oblateness of (2.08 +0.19 or -0.18) x 10 to the 2nd is found and, assuming a stratospheric temperature of 120 K, a value of 0.6 percent is inferred (with an uncertainty of a factor of 10) for the methane mixing ratio (CH4/H2) at 0.3 mbar. The latter value may indicate supersaturation of methane in Neptune's stratosphere.

  11. Characterization of Enigmatic Saturn's Ring B by Cassini Radio Occultations

    NASA Astrophysics Data System (ADS)

    Marouf, E. A.; French, R. G.; Rappaprt, N. J.; McGhee, C. A.; Thomson, F. S.; Wong, K.; Anabtawi, A.

    2007-12-01

    Cassini radio occultation observations of the extinction and near-forward scattering of 0.94, 3.6, and 13 cm- wavelengths sinusoidal signals have shed much new light on the structure and physical properties of Saturn's main ring system, especially enigmatic Ring B. As of June 2007, the occultations covered 15 distinct ring longitudes and roughly two distinct ranges of ring opening angle B; the first 12 covered B = 19.5-23.5 deg, and the last three B =14-15 deg. Four sub-regions of Ring B, identified as B1 to B4 (bounded by rough ring radius = 92, 99, 104.5, 110, 117.5 thousand km) exhibit clearly distinct structure (Marouf et al., 38th DPS Meeting, 38.05, 2006). Region B2, in particular, is characterized by remarkable 'bi-stable' states, where the optical depth abruptly flip-flops between optical depth of about 2 and more than 5. We consider observational evidence that bear on physical characterization of the observed structure (particle sizes, particle-cluster-sizes and orientation, spatial cluster density, vertical ring profile and physical thickness, ...). On the signal extinction side, this includes differential extinction of the three radio signals, and apparent variation of optical depth with observation longitude and ring opening angle (azimuthal asymmetry). On the forward scattered signal side, it includes strength, bandwidth, spectral shape and Doppler drift-rate of observed spectrogram features. We present representative results for selected features in regions B1, B2, and B4. Of particular interest is the detection of quasi-periodic ring structure of period roughly 100 meters in region B2 (and perhaps B4). In contrast with the prevalent gravitational wakes, the periodic structure is not azimuthally inclined and appears to be an independent structure superposed on the background wake structure (Thomson et al., submitted 2007).

  12. Ionospheric imaging using merged ultraviolet airglow and radio occultation data

    NASA Astrophysics Data System (ADS)

    Stephan, Andrew W.; Budzien, Scott A.; Finn, Susanna C.; Cook, Timothy A.; Chakrabarti, Supriya; Powell, Steven P.; Psiaki, Mark L.

    2014-09-01

    The Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) and GPS Radio Occultation and Ultraviolet Photometry-Colocated (GROUP-C) experiments are being considered for flight aboard the Space Test Program Houston 5 (STP-H5) experiment pallet to the International Space Station (ISS). LITES is a compact imaging spectrograph that makes one-dimensional images of atmospheric and ionospheric ultraviolet (60-140 nm) airglow above the limb of the Earth. The LITES optical design is advantageous in that it uses a toroidal grating as its lone optical surface to create these high-sensitivity images without the need for any moving parts. GROUP-C consists of two instruments: a nadir-viewing ultraviolet photometer that measures nighttime ionospheric airglow at 135.6 nm with unprecedented sensitivity, and a GPS receiver that measures ionospheric electron content and scintillation with the assistance of a novel antenna array designed for multipath mitigation. By flying together, these two experiments form an ionospheric observatory aboard the ISS that will provide new capability to study low- and mid-latitude ionospheric structures on a global scale. This paper presents the design and implementation of the LITES and GROUP-C experiments on the STP-H5 payload that will combine for the first time high-sensitivity in-track photometry with vertical spectrographic imagery of ionospheric airglow to create high-fidelity images of ionospheric structures. The addition of the GPS radio occultation measurement provides the unique opportunity to constrain, as well as cross-validate, the merged airglow measurements.

  13. Pluto's Atmosphere from the July 2010 Stellar Occultation

    NASA Astrophysics Data System (ADS)

    Person, Michael J.; Elliot, J. L.; Bosh, A. S.; Gulbis, A. A. S.; Jensen-Clem, R.; Lockhart, M. F.; Zangari, A. M.; Zuluaga, C. A.; Levine, S. E.; Pasachoff, J. M.; Souza, S. P.; Lu, M.; Malamut, C.; Rojo, P.; Bailyn, C. D.; MacDonald, R. K. D.; Ivarsen, K. M.; Reichart, D. E.; LaCluyze, A. P.; Nysewander, M. C.; Haislip, J. B.

    2010-10-01

    We have observed the 4 July 2010 stellar occultation by Pluto as part of our program of monitoring Pluto's atmospheric changes over the last decade. Successful observations were obtained from three sites: Cerro Calan and Cerro Tololo, Chile, as well as the HESS-project site (High Energy Stereoscopic System) in southwestern Namibia. Successful telescope apertures ranged from 0.45 m to 1.0 m and resulted in seven occultation light curves for the event from among the three sites. Simultaneous analysis of the seven light curves indicates that Pluto's atmosphere continues to be stable, as the calculated atmospheric radii are consistent with those detected in 2006 (Elliot et al., AJ 134, 1, 2007) and 2007 (Person et al., AJ 136, 1510, 2008), continuing the stability that followed the large pressure increase detected between 1988 (Millis et al., Icarus 105, 282, 1993) and 2002 (Elliot et al., Nature 424, 165, 2003). We will present the overall astrometric solution as well as current profiles for Pluto's upper atmospheric temperature and pressure obtained from inversion of the light curves (Elliot, Person, and Qu, AJ 126, 1041, 2003). This work was supported, in part, by grants NNX10AB27G to MIT, NNX08AO50G to Williams College, and NNH08AI17I to the USNO from NASA's Planetary Astronomy Division. The 0.75-m ATOM (Automatic Telescope for Optical Monitoring) light curve was obtained with the generous assistance of the HESS-project staff, arranged by Stefan Wagner and Marcus Hauser of the University of Heidelberg. The 0.45-m Goto telescope at Cerro Calán National Astronomical Observatory, Universidad de Chile, was donated by the Government of Japan. PROMPT (Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes) observations at Cerro Tololo were made possible by the Robert Martin Ayers Science Fund. Student participation was supported in part by NSF's REU program and NASA's Massachusetts Space Grant.

  14. Mapping Pluto's Temperature Distribution Through Twenty Years of Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Zangari, Amanda; Binzel, R. P.; Person, M. J.

    2012-10-01

    Multi-chord, high signal-to-noise Pluto occultations have been observed several times over the past two decades, including events in 1988, 2002, 2006, 2007, 2010 and 2011 (Elliot et al. 1989, 2003, 2007; Person et al. 2008, 2010, 2011). We fit separate immersion and emersion occultation light-curve models to each of the individual light curves obtained from these efforts. Asymmetries in the light curves result in the half-light temperatures for opposite sides of a single chord to differ by up to 20 Kelvin in the largest case. The temperature difference for each chord is consistent using both isothermal (b=0) and non-isothermal (e.g. b=-2.2) models based on the methodology described by Elliot & Young (1992). We examine the relationship between the location of immersion and emersion points on Pluto and these temperatures at the half-light radius and will present results for correlations between these location/temperature data and surface composition maps, Pluto geometry, and accumulated insolation patterns. This work was supported by NASA Planetary Astronomy Grant to MIT (NNX10AB27G), and NSF Astronomy and Astrophysics Grant to MIT (0707609). The authors would like to acknowledge the late Professor James L. Elliot for his efforts in beginning this work. References: Elliot, J. L., Dunham, E. W., Bosh, A. S., et al. 1989, Icarus, 77,148 Elliot, J. L., Ates, A., Babcock, B. A., et al. 2003, Nature, 424,165 Elliot, J. L., Person, M. J., Gulbis, A. A. S., et al. 2007, AJ, 134, 1 Elliot, J. L., & Young, L. A. 1992, AJ, 103, 991. Person, M. J., Elliot, J. L., Gulbis, A. A. S., et al. 2008, AJ, 136, 1510 Person, M. J., Elliot, J. L., Bosh, A. S., et al. 2010, Bulletin of the American Astronomical Society, 42, 983 Person, M. J., Dunham, E. W., Bida, T., et al. 2011, EPSC-DPS Joint Meeting 2011, 1374.

  15. Benign-malignant mass classification in mammogram using edge weighted local texture features

    NASA Astrophysics Data System (ADS)

    Rabidas, Rinku; Midya, Abhishek; Sadhu, Anup; Chakraborty, Jayasree

    2016-03-01

    This paper introduces novel Discriminative Robust Local Binary Pattern (DRLBP) and Discriminative Robust Local Ternary Pattern (DRLTP) for the classification of mammographic masses as benign or malignant. Mass is one of the common, however, challenging evidence of breast cancer in mammography and diagnosis of masses is a difficult task. Since DRLBP and DRLTP overcome the drawbacks of Local Binary Pattern (LBP) and Local Ternary Pattern (LTP) by discriminating a brighter object against the dark background and vice-versa, in addition to the preservation of the edge information along with the texture information, several edge-preserving texture features are extracted, in this study, from DRLBP and DRLTP. Finally, a Fisher Linear Discriminant Analysis method is incorporated with discriminating features, selected by stepwise logistic regression method, for the classification of benign and malignant masses. The performance characteristics of DRLBP and DRLTP features are evaluated using a ten-fold cross-validation technique with 58 masses from the mini-MIAS database, and the best result is observed with DRLBP having an area under the receiver operating characteristic curve of 0.982.

  16. Neuroleptic malignant syndrome.

    PubMed

    Ingall, T J; Tennant, C

    1986-11-01

    The neuroleptic malignant syndrome is a relatively rare but potentially fatal complication of the use of major tranquillizers; mortality may be as high as 20%. The syndrome is manifest by the onset of hyperpyrexia, muscular rigidity and tremor, impaired consciousness and autonomic dysfunction. The pathophysiology is thought to be by way of dopamine receptor blockade. The syndrome is managed by cessation of the neuroleptic medication, by supportive measures and by instituting treatment with one or more of a number of specific drugs whose use is based on theoretical considerations rather than empirical evidence of efficacy; these drugs include anticholinergics, L-dopa, bromocriptine amantidine and dantrolene sodium. Although not proven, early recognition and treatment may reduce both the mortality and the longer term morbidity of this syndrome. PMID:3773831

  17. Primary pineal malignant melanoma

    PubMed Central

    Cedeño Diaz, Oderay Mabel; Leal, Roberto García; La Cruz Pelea, Cesar

    2011-01-01

    Primary pineal malignant melanoma is a rare entity, with only thirteen cases reported in the world literature to date. We report a case of a 70-year-old man, who consulted with gait disturbance of six months duration, associated in the last month with dizziness, visual abnormalities and diplopia. No other additional melanocytic lesions were found elsewhere. The magnetic resonance showed a 25 mm expansive mass in the pineal gland that was associated with hydrocephaly, ventricular and transependimary oedema. The lesion was partially excised by a supracerebellar infratentorial approach. The histological examination revealed a melanoma. The patient received radiation therapy, but died of disease 16 weeks later. We herein review the literature on this rare tumour and comment on its clinical, radiological and histopathological features and differential diagnosis. PMID:24765293

  18. The malignant primate?

    PubMed

    de Grouchy, J

    1991-01-01

    Speciation and carcinogenesis result from genomic instability at the gametic or at the somatic levels. After an infinity of trials they occur, by chromosome rearrangements, in single individuals or in single cells and evolve by similar chromosomal or clonal evolutions. Loss of heterozygosity for the first event is essential in both processes: in evolution, a chromosomal rearrangement, a pericentric inversion or a Robertsonian fusion, must become homozygous to ensure a reproductive barrier for a new species; Knudson's two-event sequence is a similar situation in cancer. Position effect is equally important: we have shown overexpression of the SOD1 gene in the orangutan phylum probably by an intrachromosomal rearrangement; the t(9;22) in CML acts by typical position effect. Parental imprinting underlies the evolution of genome function and the unset of certain cancers. Evolution and malignancy are interweaved by viruses and oncogenes since the dawn of life. Cancer uses its intelligence to expand and to destroy the other tissues, using subtle metabolic pathways and a variety of tricks to metastasize other cells. It always wins but saws the branch on which it sits. Mankind also grows exponentially, killing thousands of other species, poisoning the oceans and soft waters, polluting the atmosphere, all for his egoistic needs. Man also travels and metastasizes other Earths. He modifies his genome or that of other species, and develops new technologies for his reproduction. He can destroy the planet in an eyeblink. To be or not to be the malignant primate, that will be the dilemma for the 21st Century. PMID:1809219

  19. Search for serendipitous TNO occultation events in X-rays with Athena

    NASA Astrophysics Data System (ADS)

    Chang, Hsiang-Kuang; Liu, Chih-Yuan; Shang, Jie-Rou

    2015-09-01

    Trans-Neptunian Objects (TNOs), which include Kuiper Belt Objects (KBOs) and yet-to-discover Oort Cloud Objects, are an important population of members of the solar system. Its population properties, such as size distribution, carry information imprinted during the early epoch of the solar system formation. TNOs smaller than about ten kilometers are not directly observable. Their existence, however, may be detected through occultation events of background targets that they cause. Search for such serendipitous occultation events have been conducted in optical and X-ray bands. Since the Fresnel scale is about 30 times smaller in X-rays, using X-ray occultation events one may explore TNOs smaller than that can be done in optical bands. Here I will report X-ray sources suitable for such a study with Athena observations. The estimated Athena detection rate of occultation events, based on different model assumptions of TNO size distribution, will also be presented.

  20. Orbit design for solar and dual satellite occultation measurements of atmospheric constituents

    NASA Technical Reports Server (NTRS)

    Brooks, D. R.; Harrison, E. F.

    1979-01-01

    Two types of satellite based occultation missions are considered for measuring atmospheric constituents. Nominal cases for each type are presented to demonstrate representative solutions to orbit design problems. For the solar occultation mode, large areas of the globe can be covered during a one year mission, but the measurements are limited to local dawn or dusk. For the dual satellite mode, with a laser aboard a second satellite to act as a source, diurnal coverage can be obtained at the expense of more complex systems and mission scenarios. In this mode, orbit pairs are selected which maintain their relative orbit plane geometry while their differing periods drive cyclic patterns of latitude coverage. A simulated one year solar occultation mission is used to illustrate one way of analyzing occultation data by averaging measurements within bands of constant latitude.