Showing papers in "Journal of Ultrasound in Medicine in 2011"

Speckle-tracking echocardiography: A new technique for assessing myocardial function

Abstract: Speckle-tracking echocardiography has recently emerged as a quantitative ultrasound technique for accurately evaluating myocardial function by analyzing the motion of speckles identified on routine 2-dimensional sonograms. It provides non-Doppler, angle-independent, and objective quantification of myocardial deformation and left ventricular systolic and diastolic dynamics. By tracking the displacement of the speckles during the cardiac cycle, strain and the strain rate can be rapidly measured offline after adequate image acquisition. Data regarding the feasibility, accuracy, and clinical applications of speckle-tracking echocardiography are rapidly accumulating. This review describes the fundamental concepts of speckle-tracking echocardiography, illustrates how to obtain strain measurements using this technique, and discusses their recognized and developing clinical applications.

Objective Sonographic Measures for Characterizing Myofascial Trigger Points Associated With Cervical Pain

Abstract: Myofascial pain syndrome is a substantial health problem in the United States, believed to affect about 23 million Americans.1 Myofascial pain syndrome is a very common, complex, yet poorly understood form of neuromuscular dysfunction consisting of motor and sensory abnormalities. It is a major progenitor of nonarticular local musculoskeletal pain and tenderness that affects every age group and is commonly recognized as “muscle knots.”2 Myofascial pain syndrome is associated with numerous pain conditions, including radiculopathies, joint dysfunction, disk abnormalities, tendonitis, and many others.3 It is characterized by myofascial trigger points, which are discrete hypersensitive hard palpable nodules located within taut bands of contractured skeletal muscle. Myofascial trigger points can be found by palpation of the soft tissue performed by a trained examiner and are painful on compression. The local twitch response is an important clinical finding that confirms the presence of a trigger point. The local twitch response is a quick, localized contraction of muscle fibers produced by strumming or snapping the taut band in a direction perpendicular to the muscle fibers. Trigger points are classified clinically as active or latent.4 An active myofascial trigger point causes spontaneous pain and may often cause general motor dysfunction (stiffness and restricted range of motion). A latent myofascial trigger point often causes motor dysfunction without pain. Pain associated with latent myofascial trigger points requires firm palpation or a mechanical stimulus to elicit.5 Otherwise, latent myofascial trigger points have all of the characteristics of active myofascial trigger points, although usually to a lesser degree.3,6 Although the specific pathophysiologic basis of myofascial trigger point development and symptoms is unknown, several promising lines of scientific study (ie, histologic, neurophysiologic, biochemical, sonographic, and somatosensory) have revealed objective abnormalities.7–13 Furthermore, our group has found that differences among active, latent, and normal sites may be evaluated objectively using diagnostic sonographic techniques, such as gray scale (2-dimensional) sonography, vibration sonoelastography, and Doppler imaging.12 Most of the investigational work on myofascial pain secondary to myofascial trigger points has involved human patients because no successful animal model has been found to elucidate how these nodules arise or how to treat them in a controlled setting. Furthermore, there are very few studies describing objective and clinically applicable methods for identifying and classifying myofascial trigger points. The few that do exist have attempted to externally quantify painful regions using electrodermal properties14 and superficial soft tissue stiffness measurements.15 Although both electrical resistance and tissue stiffness significantly changed at areas where myofascial trigger points existed, neither was able to distinguish between tissue properties of active and latent trigger points. Electromyography has also been used to measure end plate noise at myofascial trigger points before and after treatment with an acupuncture needle.16 Electromyography has shown that end plate noise at trigger point sites decreased as pain decreased after acupuncture treatment. However, only active trigger points had a local twitch response during needling.16 Human in vivo microdialysis studies of the upper trapezius muscle have found that active sites have a unique biochemical milieu compared to latent sites and palpably normal muscle. Active sites have a more acidic milieu and higher levels of inflammatory mediators, neuropeptides, catecholamines, and cytokines—substances known to be associated with persistent pain states, inflammation, and sensitization.9,10 Other noninvasive methods are currently being explored to visualize and characterize myofascial trigger points via magnetic resonance elastography.17 Magnetic resonance elastography is attractive because magnetic resonance imaging is the diagnostic standard for musculoskeletal imaging; however, it is an expensive and less accessible method compared to other imaging modalities such as sonography. Sonography is a readily available, portable, and inexpensive imaging modality, suitable for use in a physiatrist’s office to complement physical examination, guide therapeutic interventions, and evaluate treatment outcomes. Previously, our group showed the feasibility of sonography for visualizing trigger points and the surrounding soft tissue.12 We were able to visualize trigger points and score them on an ordinal scale using gray scale B-mode images, color variance elastography, and Doppler waveforms of local blood flow from 9 patients. The goal of this study was to expand on these preliminary findings to study a larger set of patients and develop quantitative measures of the soft tissue environment of myofascial trigger points. We hypothesize that the soft tissue environments of active trigger points, latent trigger points, and normal muscle differ as measured by sonoelastography and Doppler imaging. We also wanted to explore the sensitivity of these measures to change after a common treatment, dry-needling therapy, to evaluate the feasibility of this method for monitoring posttreatment clinical outcomes.

Sonographic Diagnosis of Ovarian Torsion Accuracy and Predictive Factors

Abstract: Objectives The purpose of this study was to determine the accuracy of sonographic diagnosis of ovarian torsion and the predictive value of typical sonographic signs. Methods The study included 63 women attending an ultrasound unit of a tertiary obstetrics and gynecology department in 2002 through 2008 who had suspected ovarian torsion on sonography and subsequently underwent laparoscopy. Results Sonography had diagnostic accuracy of 74.6% for ovarian torsion. Abnormal ovarian blood flow and the presence of free fluid were the most diagnostically accurate isolated sonographic signs (positive predictive values, 80.0% and 89.2%, respectively; negative predictive values, 46.2% and 46.2%). Using combinations of sonographic signs yielded higher specificity and positive predictive values and lower sensitivity and negative predictive values for ovarian torsion. The diagnostic accuracy was largely affected by the ultrasound operator (mean ± SD, 78.8% ± 16.0%; range, 60.0%-100%). Conclusions In the setting of a specialized ultrasound unit, sonographic diagnosis of ovarian torsion had high (74.6%) accuracy compared with previous reports. The absence of typical sonographic signs does not rule out ovarian torsion, especially when the clinical presentation is suggestive. Basing assessments on multiple sonographic signs, including Doppler evaluation, increases the diagnostic specificity.

Ultrasound-Guided Treatment of Meralgia Paresthetica (Lateral Femoral Cutaneous Neuropathy) Technical Description and Results of Treatment in 20 Consecutive Patients

Abstract: OBJECTIVES The purposes of this study were to describe a technique for treatment of meralgia paresthetica (lateral femoral cutaneous neuropathy) using ultrasound guidance and to report the results of treatment. METHODS Twenty consecutive patients (7 male and 13 female; age range, 23-66 years; mean, 39 years) with meralgia paresthetica confirmed by electromyography were treated with perineural injection of 1 mL of methylprednisolone acetate (40 mg/mL) and 8 mL of mepivacaine, 2%, under direct ultrasound guidance. Main outcome measures included the technical success of the procedure, visual analog scale score for the lateral femoral cutaneous nerve (pain, burning sensation, and paresthesia), and visual analog scale global quality of life score. RESULTS Technical success (successful nerve block at the distribution of the lateral femoral cutaneous nerve) was achieved in all patients. Five patients felt slight sharp pain during needle insertion. The symptoms in 16 patients (80%) diminished progressively after the first week. The 4 remaining patients (20%) required a further perineural injection. The symptoms disappeared in all patients 2 months after injection (mean visual analog scale score ± SD for lateral femoral cutaneous neuropathy at baseline, 8.1 ± 2.1; at 2 months, 2.1 ± 0.5; t = 6.2; P < .001). The mean visual analog scale quality of life scored decreased from 6.9 ± 3.2 to 2.3 ± 2.5 (t = 5.3; P < .002). CONCLUSIONS Treatment of meralgia paresthetica with ultrasound-guided perineural injections resulted in substantial symptom relief in most patients 2 months after injection. Randomized placebo-controlled trials of this treatment should be considered in the future.

Role of Sonographic Elastography in the Differential Diagnosis of Axillary Lymph Nodes in Breast Cancer

Abstract: Objectives The purpose of this study was to evaluate the diagnostic utility of sonographic elastography in differentiating reactive and metastatic axillary lymph nodes in breast cancer. Methods A total of 64 lymph nodes (reactive, n = 33; metastatic, n = 31) from 62 patients with breast cancer were examined by both B-mode sonography and elastography from April to July 2009. Two experienced radiologists retrospectively assessed B-mode sonograms by the sum of scores for 4 criteria: short diameter, shape, hilum, and cortical thickening. Elastographic images were given scores of 1 to 4 according to the percentage of high-elasticity areas in the lymph nodes. We compared the diagnostic performance of B-mode sonography, elastography, and combined examinations. We also calculated the strain ratio of the lymph node and subcutaneous fat tissue. Results The elasticity score for malignant lymph nodes (mean, 3.1) was higher than the score for benign lymph nodes (mean, 2.2; P < .0001). With a cutoff between elasticity scores of 2 and 3, elastography showed 80.7% sensitivity, 66.7% specificity, and 73.4% accuracy. With a cutoff between B-mode sonographic scores of 1 and 2, B-mode sonography showed 74.2% sensitivity and 78.8% specificity. Combined B-mode and elastographic sonography showed higher sensitivity (87.1%) than B-mode sonography alone. With a strain ratio cutoff point of 2.3, sensitivity was 82.8%, and specificity was 56.3%. Conclusions Sonographic elastography may increase the sensitivity of B-mode sonography in the detection of metastatic axillary lymph nodes.

Quantitative Measurement for Thyroid Cancer Characterization Based on Elastography

Abstract: OBJECTIVES The purpose of this study was to evaluate color thyroid elastograms quantitatively and objectively and select more effective features to differentiate benign from malignant thyroid nodules. METHODS The study was approved by the Ethics Committee of Harbin Medical University. A total of 125 cases (56 malignant and 69 benign) were analyzed in this retrospective study. The original color thyroid elastograms were transferred from the red-green-blue color space to the hue-saturation-value color space. The elasticity information was represented by the hue component of color elastograms. The lesion regions were delineated by radiologists, and statistical and textural features were extracted. Then the most effective and reliable features among them were selected by using a minimum redundancy-maximum relevance algorithm. The selected features were input to a support vector machine to differentiate benign from malignant thyroid nodules. RESULTS The classification accuracy was 93.6% when the hard area ratio and textural feature (energy) of the lesion region were used. The area under the receiver operating characteristic curve for the hard area ratio was higher than that for the strain ratio (0.97 versus 0.87; P < .01), and the area under the curve for the hard area ratio was also higher than that for the color score (0.97 versus 0.80; P < .001). The results also showed that the features were robust for lesion region delineation. CONCLUSIONS The hard area ratio is an important and quantitative metric for elastograms. Quantitative analysis of elastograms using computer-aided diagnostic techniques can improve diagnostic accuracy.

Qualitative and Semiquantitative Evaluations of Solid Breast Lesions by Sonoelastography

Abstract: OBJECTIVES Our purpose was to determine whether the combination of a qualitative elasticity scoring method and a semiquantitative strain index method by sonoelastography is useful for differentiating between benign and malignant breast masses. METHODS Seventy-eight lesions in 71 consecutive patients with solid breast masses (62 benign and 16 malignant) were prospectively included in this study. For each lesion, B-mode sonographic and sonoelastographic images were obtained. After elasticity scores had been determined with a 5-point scoring method, strain indices of the lesions were calculated using a same-level and normal-appearing breast region as an internal reference by means of strain ratio measurement. The findings were compared with histopathologic findings. With the use of receiver operating characteristic curves, the diagnostic performances of the elasticity scoring and strain index methods were determined. RESULTS The mean scores ± SD on sonoelastography were 2.69 ± 0.59 for benign lesions and 3.75 ± 0.68 for malignant lesions. The mean stiffness index values were 2.03 ± 2.67 for benign lesions and 5.97 ± 4.45 for malignant lesions. The areas under the curves were 0.864 for 5-point scoring and 0.840 for the strain index. Sensitivity and specificity were 80% and 95%, respectively, for 5-point scoring, 87.5% and 72.6% for B-mode sonography, and 80% and 93% for the strain index when a cutoff point of 3.52 was used. A semiquantitative evaluation using the strain index did not contribute to the qualitative scoring evaluation. CONCLUSIONS After 5-point scoring with sonoelastography, additional measurement with the strain index is not mandatory for differentiating between benign and malignant breast masses.

A triple-targeted ultrasound contrast agent provides improved localization to tumor vasculature

Abstract: The emergence of combination antiangiogenic cancer therapy has led to an increased demand for noninvasive modalities to monitor and evaluate tumor vasculature for determining an early treatment response. Recently, contrast-enhanced sonography was validated as a powerful tool for monitoring antiangiogenic therapy in cancer.1,2 In addition, clinical trials are ongoing to determine the importance of contrast-enhanced sonography for evaluating tumor vasculature changes during presurgical therapy.3 The evolution of contrast-enhanced sonography has led to actively targeting microbubbles to tumor vasculature to provide improved visualization of angiogenesis and vessel assessment.4 Microbubbles are gas-filled colloidal particles surrounded by a flexible outer core composed of surfactant, polymer, or lipid molecules. Originally designed to improve ultrasound visualization during cardiac shunt evaluation,5 current microbubbles are stable in the circulation with a systemic half-life of several minutes. Their small size (1–10 μm) permits pulmonary passage, yet they are large enough to resist extravasation.6 During ultrasound exposure, microbubbles expand and contract in rapid oscillation and generate a nonlinear backscattered signal that can be isolated to improve contrast relative to surrounding soft tissue. These strategies ultimately improve vasculature visualization, making microbubbles useful ultrasound contrast agents. To improve contrast-enhanced visualization of circulation and angiogenesis, targeted microbubbles have been generated that actively bind molecular markers expressed on the vessel lumen. These microbubbles are conjugated to proteins through either covalent linkage or avidin-biotin interactions.7 Although the use of avidin-biotin linkage is limited to preclinical conditions because of avidin immunogenicity, the application remains useful for investigators to explore the wide range of receptors available to improve targeting. Microbubbles conjugated with receptor-targeting ligands bind to receptors expressed on the vessel lumen in the tissue of interest. The accumulation of microbubbles through vessel wall interaction ultimately improves contrast-enhanced sonography and the visualization of angiogenesis.6 For specific targeting of microbubbles to the tumor vasculature, overexpressed receptors involved in survival mechanisms such as angiogenesis and adhesion are commonly used. Endothelial receptors involved in angiogenesis are routinely shown to be overexpressed in cancer and contribute to overall cancer progression.8-11 Vascular endothelial growth factor (VEGF) is a chemical ligand produced by cells undergoing hypoxia. It generates neovascularization by forming a chemotactic gradient for the recruitment of bone marrow-derived endothelial cells and through binding of vascular endothelial growth factor receptor 2 (VEGFR2) on preexisting endothelial cells, stimulating growth and proliferation.12 Vascular endothelial growth factor receptor 2 mediates all cellular responses to VEGF, and targeting overexpression of the receptor has led to successful strategies in antiangiogenic therapy.13-15 The targeting of microbubbles to this receptor through antibody-microbubble coupling has been shown to improve contrast-enhanced sonography.16,17 Another commonly overexpressed surface molecule in tumor endothelial cells is the cell adhesion molecule P-selectin,15 which is expressed on stimulated endothelial cells and activated platelets. It participates in the recruitment of leukocytes to areas of inflammation, which are common in the tumor vasculature.18,19 In addition, the presence of P-selectin permits the adhesion of platelets and cancer cells to the tumor endothelium. Recruitment of activated platelets has been shown to induce localized production of VEGF, thereby stimulating angiogenesis and overall tumor enrichment.20 Techniques in contrast-enhanced sonography have used the expression of P-selectin in echocardiography and atherosclerotic plaque detection with P-selectin–targeted microbubbles.21,22 The overexpression of P-selectin in the tumor vasculature by stimulated endothelial cells makes it a viable target for intravascular microbubble binding. Integrins mediate attachment and interactions between cells and their surrounding tissues, which include neighboring cells and the extracellular matrix.23 αVβ3-Integrin is commonly overexpressed in the vasculature of breast cancer.24 The αVβ3-Integrins are involved in leukocyte recruitment, tumor progression, and angiogenesis and have been targeted in many cancer therapies.25-27 Targeting by antibody- or binding peptide-labeled microbubbles has been shown to improve contrast-enhanced sonography of the tumor vasculature.17,28 Improvements in contrast-enhanced sonography have been driven in part by the need for sensitive detection and characterization of vascular abnormalities. First-generation targeted microbubbles were single-targeted microbubbles to enhance visualization of inflammation and tumor angiogenesis.7,29 Soon thereafter, dual-targeted microbubbles emerged as superior agents for targeted contrast-enhanced sonography. For tumor vasculature imaging, dual combinations of VEGFR2 and αVβ3-integrin,17 P-selectin and vascular cell adhesion molecule 1,21 and intercellular adhesion molecule 1 and sialyl Lewisx30 were all shown to improve visualization over their single-targeted counterparts. Triple-targeted microbubbles may further improve contrast-enhanced sonography. In this report, microbubbles targeted to the commonly overexpressed vasculature receptors αVβ3-integrin, P-selectin, and VEGFR2 were used in a triple-targeted strategy to enhance microbubble binding and overall visualization of tumor vasculature.

Differentiation of Benign From Malignant Thyroid Lesions Calculation of the Strain Ratio on Thyroid Sonoelastography

Abstract: Objectives Initial data suggest that elastography can improve the specificity of sonography for differentiating benign and malignant thyroid lesions. The primary objective of this study was to compare quantitative sonoelastography to conventional qualitative sonoelastography and sonography for thyroid nodule characterization. Methods Ninety-eight thyroid masses (53 benign and 45 malignant) were examined with conventional sonography and sonoelastography. The images were classified into 4 patterns according to a previously proposed classification. In addition, strain ratios of thyroid tissue to the nodule were calculated. Receiver operating characteristic curve analysis was used to compare the diagnostic performance of the strain ratio and that of conventional sonography. The final diagnosis was obtained from histologic findings. Results When a cutoff point of 3.79 was introduced, significantly different strain ratios for benign (mean ± SD, 2.97 ± 4.35) and malignant (11.59 ± 10.32) lesions was obtained (P < .0001). The strain ratio measurement had 97.8% sensitivity and 85.7% specificity. The area under the curve for the strain ratio was 0.92, whereas that for the 4-point scoring system was 0.85. Of the conventional sonographic patterns, microcalcification had the highest area under the curve, at 0.72. Conclusions Strain ratio measurement of thyroid lesions is a fast standardized method for analyzing stiffness inside examined areas. Used as an additional tool with B-mode sonography, it helps increase the diagnostic performance of the examination.

Use of Sonography for Rapid Identification of Esophageal and Tracheal Intubations in Adult Patients

Abstract: Objectives The aim of this study was to investigate the usefulness of sonography for verifying tracheal tube placement within 3 seconds in adult surgical patients. Methods This was a blinded prospective randomized study. The anesthesiologist placed the tracheal tube randomly in the trachea (n = 75) or in the esophagus (n = 75) with direct laryngoscopy. A sonographer identified all tracheal and esophageal intubations. The transducer was placed transversely on the neck just superior to the suprasternal notch. The position of the tracheal tube was determined by the sonographer within 3 seconds of tracheal tube placement in the trachea or in the esophagus. Results We successfully identified 150 correct tracheal tube placements in tracheas and esophagi, resulting in sensitivity of 100% (95% confidence interval, 84%-100%) and specificity of 100% (95% confidence interval, 84%-100%). Conclusions This investigation shows that sonography for confirming tracheal intubation is a fast and effective technique.

Amniotic fluid and the clinical relevance of the sonographically estimated amniotic fluid volume: oligohydramnios.

Abstract: The amniotic fluid volume (AFV) is regulated by several systems, including the in-tramembranous pathway, fetal production (fetal urine and lung fluid) and uptake (fetal swallowing), and the balance of fluid movement via osmotic gradients. The normal AFV across gestation has not been clearly defined; consequently, abnormal volumes are also poorly defined. Actual AFVs can be measured by dye dilution techniques and directly measured at cesarean delivery; however, these techniques are time-consuming, are invasive, and require laboratory support, and direct measurement can only be done at cesarean delivery. As a result of these limitations, the AFV is estimated by the amniotic fluid index (AFI), the single deepest pocket, and subjective assessment of the AFV. Unfortunately, sonographic estimates of the AFV correlate poorly with dye-determined or directly measured amniotic fluid. The recent use of color Doppler sonography has not improved the diagnostic accuracy of sonographic estimates of the AFV but instead has led to overdiagnosis of oligohydramnios. The relationship between the fixed cutoffs of an AFI of 5 cm or less and a single deepest pocket of 2 cm or less for identifying adverse pregnancy outcomes is uncertain. The use of the single deepest pocket compared to the AFI to identify oligohydramnios in at-risk pregnancies seems to be a better choice because the use of the AFI leads to an increase in the diagnosis of oligohydramnios, resulting in more labor inductions and cesarean deliveries without any improvement in peripartum outcomes.

Comparison of Sonography and Computed Tomography as Imaging Tools for Assessment of Airway Structures

Abstract: Objectives The aim of this study was to compare airway anatomic parameters as measured by sonography and computed tomography (CT). Methods Fifteen adult patients underwent CT followed by sonography of the anterior neck under standard conditions. A radiologist and an anesthesiologist with experience in airway imaging examined the scans and performed measurements of specific airway parameters: distance to the posterior surface of the tongue, thickness of the submental region, hyomental distance, depth of the epiglottis from skin (above and below the hyoid bone), thyrohyoid distance, depth of the arytenoid cartilage from skin, and fat pad thickness at the thyroid cartilage. After performing the measurements, they compared the images by the two modalities for descriptions of the structures. Means and SDs were calculated for the measurements, and a paired t test was performed to determine statistically significant differences in the measurements by sonography and CT. Results The means of all parameters were closely related except hyomental distance (sonography, 5.23 ± 0.58 cm; CT, 3.50 ± 0.42 cm). The paired t test showed that the mean values for depth of the epiglottis below the hyoid (3.89 versus 4.17 cm; P = .31), thyrohyoid distance (1.03 versus 1.02 cm; P = .95), and depth of the arytenoid cartilage (2.90 versus 2.66 cm; P = .21) were not significantly different as measured by sonography and CT, respectively. Conclusions The study shows that sonography can reliably image all of the structures visualized by CT, and in general, infrahyoid parameters agree well between the two modalities, as opposed to suprahyoid parameters, which may be affected by unintentional head extension.

Further evidence against the reliability of the human chorionic gonadotropin discriminatory level.

Abstract: Objectives The human chorionic gonadotropin (hCG) discriminatory level-the maternal serum β-hCG level above which a gestational sac should be consistently visible on sonography in a normal pregnancy--has been reported to be 1000 to 2000 mIU/mL for transvaginal sonography. We assessed whether a woman with a β-hCG above 2000 mIU/mL and no intrauterine fluid collection on transvaginal sonography can subsequently be found to have a live intrauterine gestation and, if so, what the prognosis is for the pregnancy. Methods We identified all women scanned between January 1, 2000, and December 31, 2010, who met the following criteria: serum β-hCG testing and transvaginal sonography were performed on the same day; β-hCG was positive and sonography showed no intrauterine fluid collection; and a live intrauterine pregnancy was subsequently documented. We tabulated the β-hCG levels in these cases and assessed pregnancy outcome. Results A total of 202 patients met the inclusion criteria, including 162 (80.2%) who had β-hCG levels below 1000 mIU/mL on the day of the initial scan showing no intrauterine fluid collection, 19 (9.4%) with levels of 1000 to 1499, 12 (5.9%) 1500 to 1999, and 9 (4.5%) above 2000 mIU/mL. There was no significant relationship between initial β-hCG level and either first-trimester outcome or final pregnancy outcome (P > .05, logistic regression analysis and Fisher exact test). The highest β-hCG was 6567 mIU/mL, and the highest value that preceded a liveborn term baby was 4336 mIU/mL. Conclusions The hCG discriminatory level should not be used to determine the management of a hemodynamically stable patient with suspected ectopic pregnancy, if sonography demonstrates no findings of intrauterine or ectopic pregnancy.

The Importance of Venous Doppler Velocimetry for Evaluation of Intrauterine Growth Restriction

Abstract: The management of growth-restricted fetuses requires accurate diagnosis to optimize the timing of delivery. Doppler velocimetry is the only noninvasive method for assessing the fetoplacental hemodynamic status. This review will give a critical overview of the current knowledge on fetal venous blood flow in pregnancies complicated by in-trauterine growth-restricted fetuses. Adaptation of the circulation in intrauterine growth-restricted fetuses is described. Normal and abnormal venous Doppler waveforms are presented. Correlations of abnormal waveforms with the presence of acidemia and perinatal outcomes are emphasized. Limitations of venous Doppler velocimetry for optimizing the time for delivery and the perinatal outcome are also presented.

Epidermal cysts in the superficial soft tissue: sonographic features with an emphasis on the pseudotestis pattern.

Abstract: OBJECTIVES The purposes of this study were to report the sonographic features of superficial epidermal cysts with an emphasis on the characteristic pseudotestis appearance and to highlight the spectrum of ancillary findings. METHODS The medical records and sonographic studies of all cases of surgically proven epidermal cysts (n = 42) from January 2005 through December 2009 were reviewed. Twenty-six epidermal cysts (62%) that appeared on sonography as ovoid nodules with homogeneous low to medium echoes, simulating a testicle, were included in the pseudotestis group. The other 16 epidermal cysts (38%) without the pseudotestis pattern were included in the nonpseudotestis group. The age, sex, lesion size, length to width ratio, sonographic appearances, and frequencies of rupture and infection were compared between the groups. RESULTS Epidermal cysts in the nonpseudotestis group presented as heterogeneously echoic or lobulated nodules or had a concentric ring or target appearance. There were no significant differences in the age, sex, lesion size, and length to width ratio between the groups. The pseudotestis group had significantly higher frequencies of intralesional bright echogenic reflectors and filiform anechoic areas than the nonpseudotestis group (P < .01). There were no significant differences in the associated ancillary sonographic features, including posterior acoustic enhancement, dermal attachment, focal dermal protrusion, and frequencies of rupture and infection between the groups. CONCLUSIONS In this study, two-thirds of the superficial epidermal cysts had a characteristic pseudotestis pattern on sonography, whereas the others could be suspected by recognition of the ancillary sonographic findings, including dermal attachment and focal dermal protrusion or a distinctive concentric ring or target pattern.

A Novel Nanosonosensitizer for Sonodynamic Therapy In Vivo Study on a Colon Tumor Model

Abstract: OBJECTIVES The particles in a liquid decrease the ultrasonic intensity threshold needed for cavitation onset. In this study, a new nanoconjugate composed of protoporphyrin IX and gold nanoparticles was used as a nucleation site for cavitation. The nonradiative relaxation time of protoporphyrin IX in the presence of gold nanoparticles is longer than the similar time without gold nanoparticles. METHODS This study was conducted on colon carcinoma tumors in BALB/c mice. The tumor-bearing mice were randomly divided into 6 groups (each containing 15 mice): (1) control, (2) protoporphyrin IX, (3) gold nanoparticle-protoporphyrin IX conjugate, (4) ultrasound alone, (5) ultrasound + protoporphyrin IX, and (6) ultrasound + gold nanoparticle-protoporphyrin IX conjugate. In the respective groups as indicated above, protoporphyrin IX or the gold nanoparticle-protoporphyrin IX conjugate was injected into the tumors. Ultrasound irradiation was performed on the tumors 24 hours after injection. Antitumor effects were estimated by evaluation of the relative tumor volume, doubling time, and 5-folding time for the tumors after treatment. The cumulative survival fraction of the mice and percentage of the lost tissue volume (treated) were also assessed in the different groups. RESULTS A significant difference in the average relative volumes of the tumors 13 days after treatment was found between the ultrasound + gold nanoparticle-protoporphyrin IX group and the other groups (P < .05). The longest doubling and 5-folding times were observed in the ultrasound + gold nanoparticle-protoporphyrin IX and ultrasound + protoporphyrin IX groups. CONCLUSIONS Protoporphyrin IX conjugated to gold nanoparticles has been introduced as a promising compound and a new sonosensitizer for improving the tumor response to sonodynamic therapy by reducing the relative tumor volume and increasing the cumulative survival fraction.

The thermal index: its strengths, weaknesses, and proposed improvements.

Abstract: The thermal index (TI) has been used as a relative indicator of thermal risk during diagnostic ultrasound examinations for many years. It is useful in providing feedback to the clinician or sonographer, allowing assessment of relative, potential risks to the patient of an adverse effect due to a thermal mechanism. Recently, several shortcomings of the TI formulations in quantifying the risk to the patient have been identified by members of the basic scientific community, and possible improvements to address these shortcomings have been proposed. For this reason, the Output Standards Subcommittee of the American Institute of Ultrasound in Medicine convened a subcommittee to review the strengths of the TI formulations as well as their weaknesses and proposed improvements. This article summarizes the findings of this subcommittee. After a careful review of the literature and an assessment of the cost of updating the TI formulations while maximizing the quality of patient care, the Output Standards Subcommittee makes the following recommendations: (1) some inconsistencies in the current TI formulations should be resolved, and the break point distance should be redefined to take focusing into consideration; (2) an entirely new indicator of thermal risk that incorporates the time dependence not be implemented at this time but be included in continuing efforts toward standards or consensus documents; (3) the exponential dependence of risk on temperature not be incorporated into a new definition of the TI formulations at this time but be included in continuing efforts toward standards or consensus documents; (4) the TI formulations not be altered to include nonlinear propagation at this time but be included in continuing efforts toward standards or consensus documents; and (5) a new indicator for risk from thermal mechanisms should be developed, distinct from the traditional TI formulations, for new imaging modalities such as acoustic radiation force impulse imaging, which have more complicated pulsing sequences than traditional imaging.

Sonographically guided tendon sheath injections are more accurate than blind injections: implications for trigger finger treatment.

Abstract: Objectives Trigger finger is frequently treated with tendon sheath injections. This cadaveric study evaluated the accuracy and safety of blind and sonographically guided tendon sheath injections. To our knowledge, a study that precisely mapped the locations of material injected into the tendon sheath has not been reported previously. Methods A total of 40 fingers (excluding thumbs) of 5 fresh cadavers were used. Methylene blue dye was injected into the flexor tendon sheath using either a blind or sonographically guided injection technique (20 fingers for each technique). The location of the dye was then determined via dissection. Results Dye was observed only in the tendon sheath (ie, optimal outcome) in 70% of sonographically guided injections and 15% of blind injections (P = .001). Dye was observed in the tendon proper (ie, unsafe outcome) in 30% of blind injections and 0% of sonographically guided injections (P = .02). Conclusions We found that sonographically guided tendon sheath injections were more accurate and may be potentially safer than blind injections. These findings suggest that sonographically guided injections should be considered over blind injections when treating trigger finger.

Sonography of the spleen.

Abstract: This pictorial essay will review and discuss the aspects of differential diagnosis with splenic sonography, including recent literature and exemplary pictorial sonographic cases. Although the spleen is well evaluated by computed tomography and magnetic resonance imaging, sonography has certain advantages, including its ubiquitous availability, lack of ionizing radiation, and low cost. Sonography of the spleen plays an important role in emergency diagnosis of splenic rupture and hemorrhage. The additional use of contrast-enhanced sonography can improve the diagnostic validity. Depending on the indication, sonography of the spleen is especially important for oncologic differential diagnosis of focal lesions, follow-up examinations, and image guidance of therapeutic interventions.

Cervical Length Changes From the First to Second Trimester of Pregnancy, and Prediction of Preterm Birth by First-Trimester Sonographic Cervical Measurement

Abstract: Objectives The purpose of this study was to examine the evolution of cervical length from the first to second trimester of pregnancy and the value of first-trimester cervical measurement in the prediction of preterm delivery. Methods We conducted a longitudinal prospective study. Cervical length was measured by transvaginal sonography at 11 to 14 weeks (Cx1), 16 to 19 weeks (Cx2), and 20 to 24 weeks (Cx3). Results Eight hundred singleton pregnancies were studied. The median cervical lengths were 33 mm for Cx1 and 31 mm for Cx2 and Cx3. Significant independent predictors for cervical length were maternal weight, height, and history of cervical surgery for Cx1, maternal height, history of cervical surgery, and history of preterm delivery for Cx2, and history of cervical surgery, history of first-trimester miscarriage, and history of spontaneous preterm delivery for Cx3. Mean cervical length shortening was 2.36 mm between Cx1 and Cx3. In the subgroups of women with previous cervical surgery and history of previous preterm birth, cervical shortening was significantly more prominent. The median Cx1 was significantly shorter in the women who subsequently delivered preterm; Cx1 predicted preterm delivery before 34 weeks (odds ratio, 0.746; 95% confidence interval, 0.649-0.869) and preterm delivery before 32 weeks (odds ratio, 0.734; 95% confidence interval, 0.637-0.912). Conclusions Cervical length in the first trimester depends on maternal characteristics and a history of cervical surgery. The cervix exhibits minimal changes from 11 to 24 weeks for most women, although the shortening is more prominent in women with a history of cervical surgery or preterm delivery. First-trimester cervical length measurement can predict preterm delivery.

Fertility performance and obstetric outcomes among women with previous cesarean scar pregnancy.

Abstract: Objectives The purpose of this study was to assess fertility performance and obstetric outcomes after treatment of cesarean scar pregnancy. Methods We conducted a retrospective study in a large tertiary hospital in Israel. The study included 18 women with a diagnosis of cesarean scar pregnancy between 2000 and 2009. Results The incidence of cesarean scar pregnancy among our parturient patients was 1 per 3000 for the general obstetric population and 1 per 531 among those with at least 1 cesarean delivery. Sixteen were treated primarily with methotrexate. Two were treated primarily by surgery, and 2 more were treated by surgery after failed methotrexate treatment. After cesarean scar pregnancy treatment, 7 women conceived spontaneously, and 1 conceived by in vitro fertilization–intracytoplasmic sperm injection. The remaining 10 (55%) did not wish to conceive again. Two of the women who became pregnant (25%) had recurrent cesarean scar pregnancy. Conclusions This study shows encouraging results for fertility performance and obstetric outcomes after treatment of cesarean scar pregnancy. Nevertheless, the risk of recurrent cesarean scar pregnancy is not negligible.

Sonographically Guided Transthoracic Biopsy of Peripheral Lung and Mediastinal Lesions Role of Contrast-Enhanced Sonography

Abstract: Objectives The purpose of this study was to assess the impact of contrast-enhanced sonography on sonographically guided transthoracic needle biopsy of lung lesions. Methods A total of 121 patients underwent sonographically guided transthoracic needle cutting biopsy. Of the 121 patients, 62 (contrast-enhanced sonography group) underwent contrast-enhanced sonography before biopsy, and the information from contrast-enhanced sonography was used to optimize the biopsy procedure. The remaining 59 patients constituted the non-contrast-enhanced sonography group. The enhancement patterns and echogenicity were evaluated by the consensus of 2 sonographers. The diagnostic efficacy was compared between the contrast-enhanced and non-contrast-enhanced sonography groups. Results The enhancement intensity and extent varied greatly among different thoracic lesions, and an anechoic area (necrosis) was revealed in 26 of 62 lesions (41.9%) lesions after administration of the contrast agent. The overall diagnostic accuracy of sonographically guided transthoracic biopsy in this study was 85.9% (104 of 121). In the contrast-enhanced sonography group, the initial biopsy led to correct diagnosis in 58 of 62 lesions (93.6%). In the non-contrast-enhanced sonography group, the initial biopsy led to correct diagnosis in 46 of 59 lesions (78.0%). The difference in the diagnostic accuracy between the contrast-enhanced and non-contrast-enhanced sonography groups was statistically significant (P Conclusions Contrast-enhanced sonography enables differentiation of viable from necrotic portions of thoracic lesions and has a positive impact on the diagnostic efficacy of sonographically guided transthoracic needle biopsy.

Screening for carpal tunnel syndrome using sonography.

Abstract: Methods—The flattening ratio of the median nerve, bowing of the flexor retinaculum, and cross-sectional area of the median nerve were collected in the forearm, at the radiocarpal joint, and at the level of the pisiform in both symptomatic patients and asymptomatic control participants. Electrodiagnostic testing was completed in symptomatic patients as a diagnostic standard. Results—Median nerve measurements were collected from 166 wrists of symptomatic and asymptomatic participants. The flattening ratio did not show any correlation to electrodiagnostic testing and was identical between both symptomatic and asymptomatic participants. Moderate to strong correlations were noted between electrodiagnostic testing results and sonographic measurements of the cross-sectional area at the pisiform, retinacular bowing, and both the ratio and change of the cross-sectional area between the forearm and pisiform. The area under the curve was large for all receiver operating characteristic curves for each measurement (0.759–0.899), and sensitivity was high (80.4%–82.4%). Conclusions—Measurement of swelling through a ratio or absolute change had similar diagnostic accuracy as individual measurement of the cross-sectional area within the carpal tunnel. These measures may be useful for improving accuracy in more diverse clinical populations. Further refinement of protocols to identify the largest crosssectional area within the carpal tunnel region and statistical methods to analyze clustered, multilevel outcome data are recommended to improve diagnostics.

Reliable Measurement Procedure of Virtual Touch Tissue Quantification With Acoustic Radiation Force Impulse Imaging

Abstract: OBJECTIVES The purpose of this study was to find a reliable procedure for performing virtual touch tissue quantification of the liver. METHODS Twenty healthy volunteers were enrolled after informed consent was obtained. The liver and spleen of each volunteer were examined on the same day by two different sonologists. The shear wave velocity values at deep and superficial locations of the right and left lobes of the liver and the spleen were obtained before and after food consumption and with and without deep inspiration. The measurements were performed 5 times in each location, and the mean shear wave velocities were recorded. RESULTS No statistically significant difference was found between the mean shear wave velocities obtained by the two operators. A difference was found between the velocities obtained in the deep portion of the right lobe (5.5 cm from the probe; mean ± SD, 1.17 ± 0.25 m/s on the intercostal scan and 1.35 ± 0.45 m/s on the subcostal scan) and the superficial portion (3.5 cm; 1.56 ± 0.43 and 1.74 ± 0.74 m/s; P < .001; P < .002, respectively), and the values obtained in the deep portion of the right lobe on the intercostal scan were lower than those obtained on the subcostal scan (P < .05). There were no differences in the mean shear wave velocities of the liver before and after food consumption or with and without deep inspiration. The velocities of the spleen did not differ before and after food consumption (2.33 ± 0.47 versus 2.39 ± 0.58 m/s). CONCLUSIONS In healthy people, mean shear wave velocities were dependent on the measurement site in the liver, and food consumption or deep inspiration did not affect velocity measurements of the liver or spleen.

Reproducibility of shear wave velocity measurements by acoustic radiation force impulse imaging of the liver: a study in healthy volunteers.

Abstract: OBJECTIVES The purposes of this study were to investigate interobserver reproducibility using acoustic radiation force impulse imaging and to develop an acoustic radiation force impulse scoring system. METHODS Fifty healthy volunteers with normal liver function test values were selected for the study. Shear wave velocity measurements, expressed in meters per second, were taken in a deep portion of liver segment 6. Two observers with different levels of experience performed the measurements independently and blindly. RESULTS All of the measurements taken by the 2 observers were valid, even in volunteers with a body mass index of greater than 28 kg/m(2). The results point to very good interobserver reproducibility of shear wave velocity measurements, with an intraclass coefficient correlation of 0.86 (P < .001). CONCLUSIONS The results of this study show that shear wave velocity measurements using the acoustic radiation force impulse technique and a standardized protocol are accurate and reproducible.

Comparison of Real-time Sonoelastography With T2-Weighted Endorectal Magnetic Resonance Imaging for Prostate Cancer Detection

Abstract: Objectives The purpose of this study was to compare the value of real-time sonoelastography with T2-weighted endorectal magnetic resonance imaging (MRI) for prostate cancer detection. Methods Thirty-three patients with an elevated prostate-specific antigen level were investigated with real-time sonoelastography and T2-weighted endorectal MRI for prostate cancer diagnosis before systematic prostate biopsy. Real-time sonoelastography was performed to assess prostate tissue elasticity, and hard areas were considered suspicious for prostate cancer. Low–signal intensity nodules on T2-weighted endorectal MRI were considered suspicious for prostate cancer. Imaging findings were assigned to 6 areas of the peripheral zone (sextants), and their cancer detection rates were compared. Results Overall, prostate cancer was detected in 13 of 33 patients (39.4%). Both real-time sonoelastography and T2-weighted endorectal MRI detected 11 cancer-positive patients (84.6%). Real-time sonoelastography showed 27 suspicious lesions in 198 sextants, and 15 (55.6%) were cancer positive. T2-weighted endorectal MRI showed 31 suspicious lesions in 198 sextants, and 13 (40.6%) were cancer positive. These findings resulted in sensitivity rates and negative predictive values per patient of 84.6% and 86.7%, respectively, for sonoelastography and 84.6% and 83.3% for MRI. The per-sextant analysis showed sensitivity rates and negative predictive values of 57.7% and 93.6% for sonoelastography and 50.0% and 92.2% for MRI. Conclusions Real-time sonoelastography showed comparable results as T2-weighted endorectal MRI for prostate cancer detection.

Contrast-enhanced ultrasound imaging of sentinel lymph nodes after peritumoral administration of Sonazoid in a melanoma tumor animal model.

Abstract: Objectives The purpose of this study was to compare lymphosonography (ie, contrast-enhanced ultrasound imaging [US] after interstitial injection of a US contrast agent) for the detection of sentinel lymph nodes (SLNs) in swine with naturally occurring melanoma tumors to lymphoscintigraphy using blue dye-guided surgical dissection as the reference standard. Also, we sought to determine if lymphosonography can be used to characterize SLNs. Methods Sixty-three swine with 104 melanomas were evaluated. Contrast-specific US was performed after peritumoral injection (1 mL dose) of Sonazoid (GE Healthcare, Oslo, Norway). Lymphoscintigraphy was performed after peritumoral injections of technetium Tc 99m sulfur colloid. Peritumoral injection of 1% Lymphazurin (Ben Venue Labs, Inc, Bedford, OH) was used to guide SLN resection. The accuracy of SLN detection with the two imaging modalities was compared using the McNemar test. The SLNs were qualitatively and quantitatively characterized as benign or malignant based on the lymphosonography results with histopathology and RNA analyses used as the reference standards. Results Blue dye-guided surgery identified 351 SLNs. Lymphosonography detected 293 SLNs and 11 false-positives, while lymphoscintigraphy detected 231 SLNs and 20 false-positives. The accuracy of SLN detection was 81.8% for lymphosonography, which was significantly higher than the 63.2% achieved with lymphoscintigraphy (P < .0001). The accuracy of lymphosonography for SLN characterization was 80%. When the size of the enhanced SLN was taken into consideration to characterize SLNs, the accuracy was 86%. Conclusions Lymphosonography is statistically better than lymphoscintigraphy for the detection of SLNs in this animal model. The ability to use lymphosonography as a means to characterize SLNs as benign or malignant is limited.

Limitations of Standard Echocardiographic Methods for Quantification of Right Ventricular Size and Function in Children and Young Adults

Abstract: OBJECTIVES The aim of this study was to evaluate correlation of 2-dimensional (2D) echocardiographic assessment of right ventricular (RV) and left ventricular (LV) size and function with magnetic resonance imaging (MRI) in children and young adults. METHODS Patients with repaired tetralogy of Fallot (n = 23) and those who had normal RV volumes (n = 13) and a normal ejection fraction (EF) by MRI constituted the study groups. Echocardiographic indices including the end-diastolic area (EDa), end-systolic area (ESa), fractional area change (FAC), tricuspid annular motion (TAM), RV basal diameter, and RV basal shortening fraction were compared with MRI ventricular volumes and the EF. Two echocardiographers qualitatively graded RV size and function. RESULTS In both groups, neither the RV EDa nor the ESa correlated with MRI RV volumes. Only TAM correlated with the RV EF. Qualitative assessment of the RV showed poor interobserver agreement. The LV area and FAC correlated well with MRI data. CONCLUSIONS In contrast to the LV, 2D echocardiographic indices of RV size and function, with the exception of TAM, do not correlate with MRI data.

Comparison of sonographically guided intra-articular injections at 3 different sites of the knee.

Abstract: OBJECTIVES Sonographically guided injections show more accuracy than blind injections, but there are no reports comparing sonographically guided intra-articular injection approaches. This study examined the accuracy of sonographically guided intra-articular injections at 3 different sites of the knee using medial, midlateral, and superolateral portals. METHODS Sonographically guided intra-articular injections and radiology evaluations were performed on 126 knees with osteoarthritis (Kellgren-Lawrence grade 2 or 3). Six milliliters of mixed material containing 1% lidocaine (1 mL), 20 mg of triamcinolone (1 mL), and a nonionic contrast agent (4 mL) was injected into the intra-articular space of the knee through the medial, midlateral, and superolateral portals. After the sonographically guided intra-articular injection into the knee joint, a radiographic image was taken to determine whether the injected material had reached the intra-articular space or infiltrated into the soft tissue. RESULTS Sonographically guided intra-articular injections in the midlateral portal (95%; P < .05) and superolateral portal (100%; P < .05) showed significantly higher accuracy than injections in the medial portal (75%). CONCLUSIONS Sonographically guided intra-articular injections in the midlateral or superolateral portal may increase the accuracy of knee joint injections.