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Thứ Ba, ngày 27 tháng 1 năm 2015

J U M 2-2015

Selected Abstracts
1.      Abstract 1 of 4 Original Research

Classification of Breast Tumors Using Sonographic Texture Analysis
Objectives—The purpose of this study was to evaluate a computer-aided diagnostic system with texture analysis to improve radiologists’ accuracy in identification of breast tumors as malignant or benign.
Methods—The database included 20 benign and 12 malignant tumors. We extracted 300 statistical texture features as descriptors for each selected region of interest in 3 normalization schemes (default, μ − 3σ, and μ + 3σ, where μ and σ were the mean value and standard deviation, respectively, of the gray-level intensity and 1%–99%). Then features determined by the Fisher coefficient and the lowest probability of classification error + average correlation coefficient yielded the 10 best and most effective features. We analyzed these features under 2 standardization states (standard and nonstandard). For texture analysis of the breast tumors, we applied principle component, linear discriminant, and nonlinear discriminant analyses. First–nearest neighbor classification was performed for the features resulting from the principle component and linear discriminant analyses. Nonlinear discriminant analysis features were classified by an artificial neural network. Receiver operating characteristic curve analysis was used for examining the performance of the texture analysis methods.
Results—Standard feature parameters extracted by the Fisher coefficient under the default and 3σ normalization schemes via nonlinear discriminant analysis showed high perform-ancefor discrimination between benign and malignant tumors, with sensitivity of 94.28%, specificity of 100%, accuracy of 97.80%, and an area under the receiver operating characteristic curve of 0.9714.
Conclusions—Texture analysis is a reliable method and has the potential to be used effectively for classification of benign and malignant tumors on breast sonography.
o    © 2015 by the American Institute of Ultrasound in Medicine
2.      Abstract 2 of 4 Original Research

Spleen Size in Cirrhosis of Different Etiologies
Objectives—The purpose of this study was to evaluate the impact of cirrhosis etiology on spleen size as measured by sonography and computed tomography (CT).
Methods—The spleen images of 139 patients with cirrhosis secondary to alcohol abuse, hepatitis C, or nonalcoholic steatohepatitis were reviewed retrospectively. The maximum diagonal spleen length on a single sonogram and maximum spleen diameter on axial, coronal, or sagittal CT, whichever was largest, was compared among the etiologic groups.
Results—In 127 patients who underwent sonography, the mean spleen size ± SD on sonography in the alcohol group (13.1 ± 2.5 cm) was significantly smaller than in the hepatitis C (15.0 ± 3.4 cm) and nonalcoholic steatohepatitis (15.2 ± 3.0 cm) groups (95% confidence intervals of the mean difference, 0.6 to 3.3 and 0.8 to 3.4 cm, respectively). In 87 patients who underwent CT, the mean spleen size on CT in the alcohol group (14.0 ± 2.7 cm) was smaller than in the hepatitis C (15.9 ± 3.4 cm) and nonalcoholic steatohepatitis (15.5 ± 3.6 cm) groups, but the difference was not statistically significant. The spleen sizes on both sonography and CT in 79 patients were strongly correlated (r = 0.88; P < .0001).
Conclusions—Spleen size in patients with cirrhosis varies by the etiology of the disease. Therefore, to apply spleen size as a diagnostic or prognostic criterion in this context, it is important to recognize that cutoff values derived from spleen size in one etiologic group may not produce the same results when extrapolated to another etiologic group.
o    © 2015 by the American Institute of Ultrasound in Medicine
3.      Abstract 3 of 4 Original Research

Can Renal Sonography Be a Reliable Diagnostic Tool in the Assessment of Chronic Kidney Disease?
Objectives—Kidney size has been found to be correlated with anthropometric features and kidney function. Therefore, we postulate that if the conventionally measured renal sonographic parameters (pole-to-pole length, width, and parenchymal thickness) are taken according to standardized rules and corrected for body height, their association with kidney function could be strengthened, thus helping validate renal sonographic information for a better assessment of chronic kidney disease (CKD) status.
Methods—This cross-sectional study included 72 stable adult patients with stage 1 to 4 CKD. Sonographic parameters were obtained from both kidneys and averaged, and the measurements obtained were further corrected for patients’ body height. The glomerular filtration rate (GFR) was estimated by the Chronic Kidney Disease Epidemiology Collaboration equation.
Results—Parenchymal thickness and renal length showed the highest correlation level with the GFR. This significant correlation, however, was greatly ameliorated by the correction for patients’ body height (r = 0.537; P< .001; r = 0.510; P < .001, respectively). Of note, the product of these two parameters corrected for body height showed the best degree of correlation with the GFR (r = 0.560; P < .001), as confirmed by analysis of variance after subdivision of the population into CKD stage groups according to the GFR. Receiver operating characteristic curve analysis for discrimination of a GFR of less than 60 mL/min indentified the combined parameter as the one with the highest area under the curve (0.78; 95% confidence interval, 0.66–0.89), followed renal length corrected for height (area under the curve, 0.77; 95% confidence interval, 0.66–0.88).
Conclusions—Correction of renal sonographic parameters for body height strengthens the degree of the correlation of renal sonography with the GFR. The improved correlation with the GFR makes renal sonography a reliable tool for a more complete assessment of patients with CKD.
o    © 2015 by the American Institute of Ultrasound in Medicine
4.      Abstract 4 of 4Original Research

Thyroid Malignancy Markers on Sonography Are Common in Patients With Benign Thyroid Disease and Previous Iodine Deficiency
Objectives—The purpose of this study was to evaluate the characteristics of benign thyroid nodules on sonography and ultrasound elastography in a population exposed to iodine deficiency.
Methods—We conducted a prospective systematic evaluation of preoperative thyroid sonography and elastography in patients assigned for surgical excision of benign thyroid nodules. Two experienced sonographers performed all sonographic and elastographic examinations. Thyroid nodules were evaluated by 7 generally accepted sonographic malignancy risk markers and assigned an elasticity score on elastography. The final diagnosis of a benign thyroid nodule was based on histopathologic analysis of resected thyroid gland tissue.
Results—We evaluated 232 thyroid nodules in 105 patients (86 women and 19 men). In total, 57% of the examined nodules had 1 or 2 malignancy risk markers present, and 24% did not have any markers present. A solid nodule larger than 15 mm was the most common malignancy risk marker observed (63%), followed by low elasticity (33%), microcalcifications (26%), and hypoechogenicity (15%). In an analysis stratified according to the number of nodules (solitary versus multiple), low elasticity was described more frequently in solitary nodules (61.9% versus 30.4%; P= .004). A large nodular volume was a predictor (P < .05) of microcalcifications and intranodular vascularization, whereas an absent halo sign and a solid nodule were found less frequently in nodules with larger volumes.
Conclusions—Our results show that routine preoperative malignancy risk evaluation of presumably benign thyroid nodules is of little value when performed on patients exposed to iodine deficiency.
o    © 2015 by the American Institute of Ultrasound in Medicine