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  • Artikel  (45)
  • 2010-2014  (45)
  • 2012  (45)
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  • Artikel  (45)
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  • 2010-2014  (45)
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  • 1
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    Mammographic Breast Density Patterns in Asymptomatic Mexican Women (2012)
    Hindawi
    Details
    Publikationsdatum: 2012-12-31
    Beschreibung: 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 () 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.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
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    A Retrospective Analysis of the Clinical Impact of 939 Chest Radiographs Using the Medical Records (2012)
    Hindawi
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    Publikationsdatum: 2012-12-22
    Beschreibung: Objective. Between one-third and half of all radiology examinations worldwide are probably chest studies. The aim of the current study was to retrospectively evaluate the clinical influence of chest radiography. Methods. In a tertiary referral hospital, 939 consecutive daytime chest radiography examinations were evaluated. The outcome was classified as normal, incidental, or pathologic. The referring physician’s reaction to radiologic outcome was classified as highly expected, moderately expected, or unexpected. The influence on the patients' treatment was divided into four groups from major to no influence. Results. In all, 71.6% of the studies had a highly expected outcome. Moderately expected or unexpected outcomes were noted in 36.6% of 500 pathologic examinations. Unexpected outcome was noted in 11.6% of all studies. The radiologic outcome influenced treatment in 65.4% of patients where pathology was demonstrated. Patients with normal or incidental findings had treatment influenced in 1/3 of the cases. Unexpected findings influenced treatment more than moderately expected findings. When radiological findings were highly expected, treatment was influenced in less than half of the cases. Surprisingly few chest radiology examinations were commented upon in the medical records.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
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    A Practical Approach for a Wide Range of Liver Iron Quantitation Using a Magnetic Resonance Imaging Technique (2012)
    Hindawi
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    Publikationsdatum: 2012-12-12
    Beschreibung: The goal of this study is to demonstrate a practical magnetic resonance imaging technique for quantifying a wide range of hepatic iron concentration (HIC) for hematologic oncology patients with transfusion iron overload in a routine clinical setting. To cover a wide range of values from hematologic patients, we used a dual-acquisition method with two clinically available acquisition protocols on a 1.5T MRI scanner with different ΔTEs to acquire data in two breath-holds. An in-house image postprocessing software tool was developed to generate , iron maps, and water and fat images, when fat is presented in the liver. The resulting iron maps in DICOM format are transferred to the institutional electronic medical record system for review by radiologists. The measured liver values for 28 patients ranged from to milliseconds. These values corresponded to HIC values ranging from  mg/g to  mg/g (dry weight). A moderate correlation between overall serum ferritin levels and was found with a correlation coefficient of 0.83. Repeated phantom scans confirmed that the precision of this method is better than 4% for measurements. The dual- acquisition method also improved the ability to quantify HIC of the patients with hepatic steatosis.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
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    White Matter Atrophy in Patients with Mesial Temporal Lobe Epilepsy: Voxel-Based Morphometry Analysis of T1- and T2-Weighted MR Images (2012)
    Hindawi
    Details
    Publikationsdatum: 2012-12-05
    Beschreibung: Introduction. Mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis is highly refractory to clinical treatment. MRI voxel-based morphometry (VBM) of T1-weighted images has revealed a widespread pattern of gray matter (GM) and white matter (WM) atrophy in MTLE. Few studies have investigated the role of T2-weighted images in revealing WM atrophy using VBM. Objectives. To compare the results of WM atrophy between T1- and T2-weighted images through VBM. Methods. We selected 28 patients with left and 27 with right MTLE and 60 normal controls. We analyzed T1- and T2- weighted images with SPM8, using VBM/DARTEL algorithm to extract maps of GM and WM. The second level of SPM was used to investigate areas of WM atrophy among groups. Results. Both acquisitions showed bilateral widespread WM atrophy. T1-weighted images showed higher sensibility to detect areas of WM atrophy in both groups of MTLE. T2-weighted images also showed areas of WM atrophy in a more restricted pattern, but still bilateral and with a large area of superposition with T1-weighted images. Conclusions. In MTLE, T1-weighted images are more sensitive to detect subtle WM abnormalities using VBM, compared to T2 images, although both present a good superposition of statistical maps.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
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    Parameter Optimization for Quantitative Signal-Concentration Mapping Using Spoiled Gradient Echo MRI (2012)
    Hindawi
    Details
    Publikationsdatum: 2012-11-06
    Beschreibung: Rationale and Objectives. Accurate signal to tracer concentration maps are critical to quantitative MRI. The purpose of this study was to evaluate and optimize spoiled gradient echo (SPGR) MR sequences for the use of gadolinium (Gd-DTPA) as a kinetic tracer. Methods. Water-gadolinium phantoms were constructed for a physiologic range of gadolinium concentrations. Observed and calculated SPGR signal to concentration curves were generated. Using a percentage error determination, optimal pulse parameters for signal to concentration mapping were obtained. Results. The accuracy of the SPGR equation is a function of the chosen MR pulse parameters, particularly the time to repetition (TR) and the flip angle (FA). At all experimental values of TR, increasing FA decreases the ratio between observed and calculated signals. Conversely, for a constant FA, increasing TR increases this ratio. Using optimized pulse parameter sets, it is possible to achieve excellent accuracy (approximately 5%) over a physiologic range of concentration tracer concentrations. Conclusion. Optimal pulse parameter sets exist and their use is essential for deriving accurate signal to concentration curves in quantitative MRI.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
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    Double Bolus Application in TWIST-MR-Angiography of the Cervical Arteries (2012)
    Hindawi
    Details
    Publikationsdatum: 2012-10-21
    Beschreibung: Purpose. The aim of the present work was to test the feasibility of the time-resolved MR-angiography (TWIST-MRA) of cervical arteries using double bolus injection. Material and Methods. TWIST-MRA with a temporal resolution of 8.4 seconds for each frame and a spatial resolution with a voxel size of   was performed in 24 patients. A biphasic bolus injection protocol was used with the second injection being started 21 seconds after the first contrast dye bolus. Diagnostic image quality was rated according to a 4-point scale. Results. In 12 patients (50%) no clear separation between the cervical venous and arterial vessels was evident after the first bolus injection. Using TWIST-MRA data acquired after the second bolus a sufficient diagnostic image quality (rating , mean 3.5) could be obtained in 22 of 24 patients (92%). Discussion. The double bolus injection protocol using TWIST-MRA allows for very good separation of the cervical arteries.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
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    Invalidity of SUV Measurements of Lesions in Close Proximity to Hot Sources due to “Shine-Through” Effect on FDG PET-CT Interpretation (2012)
    Hindawi
    Details
    Publikationsdatum: 2012-10-16
    Beschreibung: It is well known that many technical and physiologic factors can affect the reliability of the standardized uptake value (SUV) on FDG PET-CT. Another potential problem of which we may be aware but has not been previously discussed is significant SUV overestimation of lesions in the direct neighborhood of large hot sources, namely, areas with high FDG uptake or activity such as a tumor, myocardium, urinary bladder, kidney, or gastrointestinal tract. The magnitude of SUV overestimation of the lesions directly neighboring the large hot sources is varied among the different cases, and it is possibly secondary to “shine-through” effect of the hot sources, which would warrant further systematic investigation such as phantom simulation experiment. If the lesion is in the close territory of the hot source, measured SUV is often overestimated and invalid. Visual interpretation should be used for evaluation of FDG avidity of the lesion.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
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    Microradiography of Microcalcifications in Breast Specimen: A New Histological Correlation Procedure and the Effect of Improved Resolution on Diagnostic Validity (2012)
    Hindawi
    Details
    Publikationsdatum: 2012-10-12
    Beschreibung: Introduction. Does high-resolution visualization of microcalcifications improve diagnostic reliability? Method. X-rays were taken of mamma specimens with microcalcifications in 32 patients (10 malignant; 22 benign) using conventional radiography (12 Lp/mm) and high-resolution radiography (2000 Lp/mm). Histological sections were subsequently prepared and correlated to the microradiographic image and every calcification was assigned an exact malignant or benign histological diagnosis. Five radiologists classified single groups of calcifications in both methods according to the BIRADS classification system. Results. Using microradiography microcalcifications can be shown in high resolution at the cell level including histological correlation. In some cases, the diagnostic validity was improved by the high resolution in microradiography. In other cases, the high resolution resulted in more visible calcifications, thus giving benign calcifications a malignant appearance. In the BIRADS 2 and 3 group, the probability of malignancy was 28.6% in the conventional radiography evaluation and 37.8% in the microradiography evaluation. In the BIRADS 4 and 5 group, the probability of malignancy was 34.2% in the conventional radiography evaluation and 24.4% in the microradiography evaluation. The differences were not significant. Summary. Overall, the improved resolution in microradiography did not show an improvement in diagnostic accuracy compared to conventional radiography.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
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    The Influence of Effective Energy on Computed Tomography Number Depends on Tissue Characteristics in Monoenergetic Cardiac Imaging (2012)
    Hindawi
    Details
    Publikationsdatum: 2012-10-10
    Beschreibung: Purpose. To evaluate the influence of effective energy on computed tomography (CT) number in monoenergetic images (MEIs). Methods. Three bottle phantoms filled with water, oil, and a contrast agent were scanned at 100 and 140 kVp tube energy with a dual-source CT scanner. Cardiac dual-energy CT data was collected from 17 patients. CT numbers were measured in the 3 phantom materials and in the left ventricular cavity, myocardium, pericardial fat, and vertebral bone in MEIs from 40 to 190 keV. Results. In the phantoms, the mean CT number increased in oil whereas it decreased in the contrast agent as the energy level increased (). In clinical subjects, the mean CT numbers for the left ventricular cavity, myocardium, and vertebral bone were highest in the 40 keV images () and decreased as the energy level increased. In contrast, the CT number for pericardial fat was lowest in the 40 keV images () and increased with increasing energy. Conclusions. The influence of effective energy on CT number varies with material and tissue type in monoenergetic cardiac imaging, which could evaluate tissue characteristics through assessment of the changes in CT number associated with effective energies.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
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    Value of Perfusion CT, Transcranial Doppler Sonography, and Neurological Examination to Detect Delayed Vasospasm after Aneurysmal Subarachnoid Hemorrhage (2012)
    Hindawi
    Details
    Publikationsdatum: 2012-09-25
    Beschreibung: Background. If detected in time, delayed cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) may be treated by balloon angioplasty or chemical vasospasmolysis in order to enhance cerebral blood flow (CBF) and protect the brain from ischemic damage. This study was conceived to compare the diagnostic accuracy of detailed neurological examination, Transcranial Doppler Sonography (TCD), and Perfusion-CT (PCT) to detect angiographic vasospasm. Methods. The sensitivity, specificity, positive and negative predictive values of delayed ischemic neurological deterioration (DIND), pathological findings on PCT-maps, and accelerations of the mean flow velocity (MVF) were calculated. Results. The accuracy of DIND to predict angiographic vasospasm was 0.88. An acceleration of MFV in TCD (〉140 cm/s) had an accuracy of 0.64, positive PCT-findings of 0.69 with a higher sensitivity, and negative predictive value than TCD. Interpretation. Neurological assessment at close intervals is the most sensitive and specific parameter for cerebral vasospasm. PCT has a higher accuracy, sensitivity and negative predictive value than TCD. If detailed neurological evaluation is possible, it should be the leading parameter in the management and treatment decisions. If patients are not amenable to detailed neurological examination, PCT at regular intervals is a helpful tool to diagnose secondary vasospasm after aneurysmal SAH.
    Print ISSN: 2090-1941
    Digitale ISSN: 2090-195X
    Thema: Medizin
    Publiziert von Hindawi
    Standort Signatur Einschränkungen Verfügbarkeit
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