Color Doppler Imaging of the Appendix: Criteria to Improve Specificity for Appendicitis in the Borderline-Size AppendixJournal of Ultrasound in Medicine October 2016 35:2129-2138;Published Online First August 25, 2016, doi:10.7863/ultra.15.11064
The “Dirty Liver” as a Coincidental Finding on Sonography:Sonographic Criteria for Biliary Microhamartomas of the LiverJournal of Ultrasound in Medicine October 2016 35:2139-2145;doi:10.7863/ultra.15.11081
Classification of Carotid Plaque Echogenicity by Combining Texture Features and Morphologic CharacteristicsJournal of Ultrasound in Medicine October 2016 35:2253-2261;Published Online First August 31, 2016, doi:10.7863/ultra.15.09002
Criteria to Improve Specificity for Appendicitis in the Borderline-Size Appendix
Objectives— To test the hypothesis that continuous intramural vascular signal measuring at least 3 mm on color Doppler imaging is highly specific for appendicitis in patients with diagnostically borderline-size appendices.
Methods— Two blinded observers independently reviewed color Doppler images of the appendix in 94 consecutive patients who had undergone sonography for suspected appendicitis and whose appendices were of diagnostically borderline size (6–8 mm maximum outer diameter). Intramural vascular flow on color Doppler images was classified as absent, type 1 (only punctate and dispersed signal), or type 2 (continuous linear or curvilinear signal measuring at least 3.0 mm in long- or short-axis views). Histopathologic examination and clinical follow-up served as reference standards. Proportions were assessed by the exact binomial test.
Results— Of the 94 patients, 33 (35.1%) had type 1 flow (of whom 5 [15.2%] had appendicitis); 23 (24.5%) had type 2 flow (of whom 20 [87.0%] had appendicitis); and 38 (40.4%) had absent flow (of whom 10 [26.3%] had appendicitis). The sensitivity, specificity, and odds ratio of type 2 flow as an indicator of appendicitis were 57.1%, 94.9%, and 24.9 (P< .001), respectively; the corresponding values for type 1 flow as an indicator of normal appendices were and 47.5%, 85.7%, and 5.4 (P = .002).
Conclusions— Continuous intramural linear or curvilinear signal measuring at least 3 mm on color Doppler imaging is a highly specific, although relatively insensitive, sign of acute appendicitis in noncompressible appendices of diagnostically borderline size (6–8 mm).
The “Dirty Liver” as a Coincidental Finding on Sonography
Sonographic Criteria for Biliary Microhamartomas of the Liver
Objectives— Biliary microhamartomas of the liver are known as symptomless, benign, microscopic biliary duct deformations. The consistently improving quality of ultrasound technology has made it possible to visualize them, which has led to difficulty in distinguishing them from neoplastic liver alterations. The purpose of this study was to evaluate the appearance of biliary microhamartomas and their behavior on contrast-enhanced sonography.
Methods— We defined typical sonographic findings in biliary microhamartomas of the liver (1 main criterion and 3 secondary criteria). Nineteen patients were identified as have typical characteristics images of biliary microhamartomas as coincidental findings on liver sonography. All patients were included in a clinical follow-up program without histologic confirmation after they underwent risk assessment. Follow-up examinations were performed with B-mode sonographic examinations at 6, 12, and 18 months. In addition, in 15 patients, contrast-enhanced sonographic examinations of the liver were performed.
Results— None of the patients had a change in the number or size of the identifiable typical liver lesions (main criterion) after a mean follow-up period ± SD of 14.4 ± 6.5 months. There were also no alterations among the aforementioned secondary criteria in any of the participants. On contrast-enhanced sonography, the lesions of all patients showed a consistent pattern, with early arterial enrichment and persistent homogeneous contrast in the late portal venous phase.
Conclusions— The sonographic appearance of biliary microhamartomas is characteristic and typical enough that histologic confirmation is not always necessary. Follow-up examinations to monitor any developments are usually adequate.
Evaluation of Parathyroid Lesions With Point Shear Wave Elastography
Objectives— The aim of our study was to evaluate the shear wave velocity (SWV) of parathyroid lesions by point shear wave elastography (SWE) and to compare their stiffness with that of thyroid nodules and normal thyroid parenchyma quantitatively.
Methods— Thirty-six patients considered to have parathyroid disorders by clinical and laboratory tests and scintigraphy were enrolled in the study between January 2012 and February 2015. Conventional sonography, Doppler sonography, and the Virtual Touch tissue quantification (VTQ) method of point SWE (Siemens Medical Solutions, Mountain View, CA) were conducted with a linear transducer (4–9 MHz) while the patients were in the supine position. Then we compared our VTQ measurements with pathologic results.
Results— The 36 patients included 31 female and 5 male patients with a mean age ± SD of 49 ± 15.7 years (range, 15–79 years). The mean SWV of parathyroid hyperplasia lesions (n = 4) was 1.46 ± 0.23 m/s, whereas the mean SWV of parathyroid adenomas (n = 32) was 2.28 ± 0.50 m/s. The mean SWV of normal thyroid parenchyma (n = 36) was 1.62 ± 0.20 m/s, and the mean SWV of benign thyroid nodules (n = 21) was 2.25 ± 0.51 m/s. A significant difference was found between SWV values of normal thyroid parenchyma and parathyroid adenoma (P < .001). A cutoff value of 1.73 m/s for adenomas led to 90.0% sensitivity and 80.6% specificity.
Conclusions— The VTQ method of point SWE may contribute to the discrimination of parathyroid adenomas from the thyroid gland. However, more comprehensive studies are needed.
Classification of Carotid Plaque Echogenicity by Combining Texture Features and Morphologic Characteristics
Objectives— Anechoic carotid plaques on sonography have been used to predict future cardiovascular or cerebrovascular events. The purpose of this study was to investigate whether carotid plaque echogenicity could be assessed objectively by combining texture features extracted by MaZda software (Institute of Electronics, Technical University of Lodz, Lodz, Poland) and morphologic characteristics, which may provide a promising method for early prediction of acute cardiovascular disease.
Methods— A total of 268 plaque images were collected from 136 volunteers and classified into 85 hyperechoic, 83 intermediate, and 100 anechoic plaques. About 300 texture features were extracted from histogram, absolute gradient, run-length matrix, gray-level co-occurrence matrix, autoregressive model, and wavelet transform algorithms by MaZda. The morphologic characteristics, including degree of stenosis, maximum plaque intima-media thickness, and maximum plaque length, were measured by B-mode sonography. Statistically significant features were selected by analysis of covariance. The most discriminative features were obtained from statistically significant features by linear discriminant analysis. The K-nearest neighbor classifier was used to classify plaque echogenicity based on statistically significant and most discriminative features.
Results— A total of 30 statistically significant features were selected among the plaques, and 2 most discriminative features were obtained from the statistically significant features. The classification accuracy rates for 3 types of plaques based on statistically significant and most discriminative features were 72.03% (κ= 0.571; P < .001) and 88.14% (κ= 0.820; P < .001), respectively. The receiver operating characteristic curve for identifying anechoic plaques showed an area under the curve of 0.918 when the most discriminative features were used to train the classifier.
Conclusions— It is feasible to classify carotid plaque echogenicity by combining texture features extracted from sonograms by MaZda and morphologic characteristics.