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- Sonography of the lateral antebrachial cutaneous nerve with magnetic resonance imaging and anatomic correlation. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1475-83.
Abnormalities of the lateral antebrachial cutaneous nerve (LABCN) are associated with antecubital elbow conditions, such as distal biceps brachii tendon tears and traumatic cephalic vein phlebotomy. These can lead to lateral forearm, elbow, and wrist symptoms that can mimic other disease processes. The purpose of this study was to characterize the sonographic appearance of the LABCN using cadaveric dissection and retrospective analysis of sonographic examinations of symptomatic patients with magnetic resonance imaging correlation.For the first part of this study, a cadaveric elbow specimen was examined, and sonography was performed after dissection to identify the LABCN. Subsequently, 26 elbows in 13 patients with LABCN abnormalities were identified with sonography and retrospectively evaluated to characterize the appearance of the LABCN in both symptomatic and asymptomatic elbows.The symptomatic LABCNs showed fusiform enlargement, increased echogenicity, and loss of the normal fascicular echo texture. The mean cross-sectional area of the symptomatic nerves was 12.0 mm(2) (range, 6.1-17.2 mm(2)), with a maximum thickness of 3.5 mm (range, 2.3-5.9 mm), compared to 3.3 mm(2) (range, 1.9-5.2 mm(2)), with a maximum thickness of 1.3 mm (range, 0.9-2.2 mm), in the contralateral normal elbows.The close proximity of the LABCN to the distal biceps tendon and the cephalic vein makes it vulnerable to compression and injury in the setting of distal biceps tendon tears and traumatic phlebotomy, which may cause nerve enlargement and increased echogenicity. Awareness of the location and appearance of the LABCN on sonography is important for determining potential causes of lateral elbow and forearm pain.
- Sonographically guided distal biceps tendon injections: techniques and validation. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1461-74.
The primary purpose of this investigation was to describe and validate sonographically guided techniques for distal biceps peritendinous/intratendinous injections using a cadaveric model.A single experienced operator completed 18 sonographically guided distal biceps peritendinous injections and 15 sonographically guided distal biceps intratendinous injections in 18 unembalmed cadaveric elbow specimens (11 male and 7 female; age, 53-100 years; body mass index, 19.4-42.2 kg/m(2)). Four different peritendinous approaches were used to inject 3 mL of diluted yellow latex: (1) anterior/superficial, (2) posterior/superficial, (3) posterior/deep/short-axis (to the distal biceps tendon), and (4) posterior/deep/long-axis (to the distal biceps tendon). Three different intratendinous approaches were used to inject 1 mL of diluted blue latex: (1) anterior, (2) anterior/pronator window, and (3) posterior. The feasibility of all 7 injections was assessed by the operator in all specimens, and execution difficulty was recorded after each injection. Specimens were subsequently dissected to assess injectate placement.All 18 peritendinous distal biceps tendon injections accurately placed latex around the tendon without injecting into the tendon proper. All posterior/superficial peritendinous injections delivered injectate to the ulnar side of the tendon. All posterior/deep peritendinous injections delivered injectate to the radial side of the tendon, with the long-axis approach being technically easier than the short-axis approach. Anterior/superficial peritendinous injections delivered injectate predominantly to the anterior side of the tendon and resulted in 1 brachial artery injury. All but 1 of 15 distal biceps intratendinous injections (93%) accurately placed injectate into the tendon proper, with 1 of 5 anterior injections delivering injectate primarily deep to the paratenon. The posterior intratendinous approach was technically the easiest. No intratendinous injection resulted in neurovascular injury.Sonographically guided distal biceps peritendinous/intratendinous injections are feasible and therefore may play a role in the management of patients presenting with distal biceps tendinopathy/bursopathy.
- Use of acoustic radiation force impulse elastography to diagnose acute pancreatitis at hospital admission: comparison with sonography and computed tomography. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1453-60.
To compare the diagnostic success rate of acoustic radiation force impulse (ARFI) elastography with those of sonography and computed tomography (CT) for acute pancreatitis at hospital admission.B-mode sonography and ARFI elastography were performed on 88 patients with symptoms of acute pancreatitis and 50 healthy control participants who were admitted to our hospital between February 2013 and July 2013. Acute pancreatitis was verified in the 88 patients based on clinical and laboratory findings. Computed tomography was performed on 41 patients, and the CT results from these patients were compared with those of ARFI elastography. The appearances of the pancreases of the patients were classified into 6 groups using visual color encodings obtained with ARFI elastography. The elasticity values of pancreatic head, body, and tail regions were evaluated with Virtual Touch imaging and Virtual Touch tissue quantification (Siemens Medical Solutions, Mountain View, CA). The success rates of sonography, CT, and ARFI elastography for diagnosing acute pancreatitis at hospital admission were compared.Forty-six of the 88 patients had a diagnosis of pancreatitis by B-mode sonography; pancreatitis was diagnosed in all patients by ARFI elastography; and 10 of 41 patients could not be diagnosed by CT. The sensitivity and specificity of Virtual Touch tissue quantification were 100% and 98%, respectively, when a cutoff value of 1.63 m/s was used. The control group had color scores of 1 or 2, whereas all patients with pancreatitis had color scores of 3 to 6 on color scale evaluation with Virtual Touch imaging.Acoustic radiation force impulse elastography is a rapid, radiation-free, and noninvasive tool for diagnosis of acute pancreatitis at initial hospital admission, with a higher success rate for diagnosis of acute pancreatitis than the grayscale sonography and CT.
- Focal Fatty sparing usually does not arise in preexisting nonalcoholic diffuse homogeneous Fatty liver. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1447-52.
The purpose of this study was to investigate whether focal fatty sparing can arise in preexisting nonalcoholic diffuse homogeneous fatty liver and its clinical implications.This prospective study consisted of 2 parts. In the first part, 8598 people (5202 men and 3396 women; mean age ± SD, 43.4 ± 28.3 years; range, 18-82 years) were consecutively evaluated with sonography for abnormal liver findings; in the second part, participants with diffuse homogeneous fatty liver were followed over approximately 3 years. Sonographic findings of the participants in the first year and findings of the participants with diffuse homogeneous fatty liver in the first and third years were analyzed.In the first part, 778 of 8598 participants (9.05%) were found to have fatty liver, including 752 cases of nonalcoholic diffuse fatty liver (8.75%) and 26 cases of alcoholic fatty liver (0.30%). Of the 752 cases of nonalcoholic diffuse fatty liver, 301 participants had nonalcoholic diffuse homogeneous fatty liver, and 68 (9.04%) had focal fatty sparing. In the second part, the 301 participants with nonalcoholic diffuse homogeneous fatty liver (205 men and 96 women; mean age, 39.6 ± 10.4 years; range, 18-60 years) were followed. In the third year, 2 cases of fatty liver (0.67%) had resolved, 2 cases (0.67%) had inflammatory pseudotumors, and no focal fatty sparing was found (P < .001).The findings of this study suggest that focal fatty sparing usually does not arise in preexisting nonalcoholic diffuse homogeneous fatty liver, and a newly emerging abnormality is more likely a true lesion.
- Freehand elastography for determination of breast cancer size: comparison with B-mode sonography and histopathologic measurement. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1441-6.
Elastography assesses the strain of soft tissues and is used to enhance diagnostic accuracy in evaluating breast tumors, but minimal data exist on its ability to accurately assess tumor size. This study was performed to assess the preoperative accuracy of measuring the size of biopsyproven breast cancer lesions with elastography and conventional B-mode sonography compared with the reference standard size measured by histopathologic examination.Elastography and conventional B-mode sonography were performed on 69 women with histologically proven breast cancer, and tumor sizes on both modalities were recorded. These measurements were compared with the final pathologic size, which was used as the reference standard. The sizes and differences between sonographic, elastographic, and pathologic measurements were statistically tested, and an analysis of equivalence to the reference standard was performed using Bland-Altman plots.There was a significant difference between sizes on elastography and pathologic examination, with elastography overestimating the tumor size (P = .0187). Sonography slightly underestimated the tumor size, but this finding was not significant (P = .36). Bland-Altman plots confirmed that sonography but not elastography was an acceptable standard compared with the pathologic size.Breast elastography but not B-mode sonography overestimates the size of breast tumors compared with the final pathologic size.
- Volumetric contrast-enhanced ultrasound imaging of renal perfusion. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1427-37.
To determine whether volumetric contrast-enhanced ultrasound (US) imaging has the potential to monitor changes in renal perfusion after vascular injury.Volumetric contrast-enhanced US uses a series of planar image acquisitions, capturing the nonlinear second harmonic signal from microbubble contrast agents flowing in the vasculature. Tissue perfusion parameters (peak intensity [IPK], time to peak intensity [TPK], wash-in rate [WIR], and area under the curve [AUC]) were derived from time-intensity curve data collected during in vitro flow phantom studies and in vivo animal studies of healthy and injured kidneys. For the flow phantom studies, either the contrast agent concentration was held constant (10 μL/L) with varying volumetric flow rates (10, 20, and 30 mL/min), or the flow rate was held constant (30 mL/min) with varying contrast agent concentrations (5, 10, and 20 μL/L). Animal studies used healthy rats or those that underwent renal ischemia-reperfusion injury. Renal studies were performed with healthy rats while the transducer angle was varied for each volumetric contrast-enhanced US image acquisition (reference or 0°, 45°, and 90°) to determine whether repeated renal perfusion measures were isotropic and independent of transducer position. Blood serum biomarkers and immunohistology were used to confirm acute kidney injury.Flow phantom results revealed a linear relationship between microbubble concentrations injected into the flow system and the IPK, WIR, and AUC (R(2) > 0.56; P < .005). Furthermore, there was a linear relationship between volume flow rate changes and the TPK, WIR, and AUC (R(2) > 0.77; P < .005). No significant difference was found between the transducer angle during data acquisition and any of the perfusion measures (P > .60). After induction of renal ischemia-reperfusion injury in the rat animal model (n = 4), volumetric contrast-enhanced US imaging of the injured kidney revealed an initial reduction in renal perfusion compared to control animals, followed by progressive recovery of vascular function.Volumetric contrast-enhanced US-based renal perfusion imaging may prove clinically feasible for detecting and monitoring acute kidney injury.
- Acoustic Radiation Force for Noninvasive Evaluation of Corneal Biomechanical Changes Induced by Cross-linking Therapy. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1417-26.
To noninvasively measure changes in corneal biomechanical properties induced by ultraviolet-activated riboflavin cross-linking therapy using acoustic radiation force (ARF).Cross-linking was performed on the right eyes of 6 rabbits, with the left eyes serving as controls. Acoustic radiation force was used to assess corneal stiffness before treatment and weekly for 4 weeks after treatment. Acoustic power levels were within US Food and Drug Administration guidelines for ophthalmic safety. Strain, determined from ARF-induced displacement of the front and back surfaces of the cornea, was fit to the Kelvin-Voigt model to determine the elastic modulus (E) and coefficient of viscosity (η). The stiffness factor, the ratio of E after treatment to E before treatment, was calculated for treated and control eyes. At the end of 4 weeks, ex vivo thermal shrinkage temperature analysis was performed for comparison with in vivo stiffness measurements. One-way analysis of variance and Student t tests were performed to test for differences in E, η, the stiffness factor, and corneal thickness.Biomechanical stiffening was immediately evident in cross-linking-treated corneas. At 4 weeks after treatment, treated corneas were 1.3 times stiffer and showed significant changes in E (P= .006) and η (P= .007), with no significant effect in controls. Corneal thickness increased immediately after treatment but did not differ significantly from the pretreatment value at 4 weeks.Our findings demonstrate a statistically significant increase in stiffness in cross-linking-treated rabbit corneas based on in vivo axial stress/strain measurements obtained using ARF. The capacity to noninvasively monitor corneal stiffness offers the potential for clinical monitoring of cross-linking therapy.
- Real-time Sonographically Guided Percutaneous Dilatational Tracheostomy Using a Long-Axis Approach Compared to the Landmark Technique. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1407-15.
Sonographic evaluation of neck anatomy before performing percutaneous dilatational tracheostomy (PDT) has been shown to predict PDT success. In this study, we compared the real-time, long-axis, in-plane approach to the traditional bronchoscopically guided landmark technique.Data were analyzed from a prospectively maintained PDT database at a university tertiary care medical intensive care unit. A convenience sample of adult patients requiring PDT for prolonged mechanical ventilation dependence was enrolled. Critical care fellows, under direct supervision of an attending intensivist, performed all PDTs. Tracheostomy performance from the sonographically guided and landmark techniques was compared.Twenty-three patients were enrolled: 11 in the sonography group and 12 in the landmark group. Initial midline introducer needle puncture was achieved in 72.7% in the sonography group compared to 8.3% in the landmark group (P< .001). The mean number of introducer needle punctures ± SD was significantly lower in the sonography group compared to the landmark group (1.4 ± 0.7 versus 2.6 ± 0.9; P < .001). The total tracheostomy time was 11.4 ± 4.2 minutes in the sonography group versus 15.3 ± 6.8 minutes in the landmark group (P = .12). Sonography accurately predicted tracheal ring space insertion in 90.9% of patients. Procedural complications did not differ significantly between the groups.Percutaneous dilatational tracheostomy under real-time sonographic guidance using a long-axis approach may increase the rate of midline punctures and decrease the number of needle punctures when compared to the landmark technique. Sonographic guidance can also help guide accurate and efficient placement of a tracheostomy tube into the desired tracheal ring space.
- Cardiac sonography by the neonatologist: clinical usefulness and educational perspective. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1401-6.
Clinicians are increasingly using cardiac sonography in clinical practice. The objectives of this study were to assess the current state of clinician-performed cardiac sonography practice in the Australia-New Zealand region, with particular reference to the scope of clinical practice and type of training offered.A prospective cross-sectional survey was conducted, and an electronic Web-based questionnaire was e-mailed to neonatologists and advanced trainees in the region. Information was collected on respondents (demographics, clinician-performed cardiac sonography experience, and opinions), equipment use, and training frameworks. Main outcome measures ascertained were clinical use and educational perspectives.The overall survey response rate was 64% (113 of 176). Eighty-five percent of respondents reported that clinician-performed cardiac sonography was performed in their units, most commonly to use the physiologic information obtained in conjunction with clinical information to refine decision making. The most common clinical indication was evaluation of a hemodynamically relevant ductus arteriosus. A dedicated echocardiographic machine was available to 80% of respondents. Most respondents reported "self-directed" learning as the most common method of training. More than 85% of respondents reported having access to either on-site or off-site pediatric cardiology services.Widespread availability and use of clinician-performed cardiac sonography in units across the Australia-New Zealand region was noted. The need for a structured training program was identified.
- Increased epicardial adipose tissue thickness on transthoracic echocardiography in patients with behçet disease. [Journal Article]
- J Ultrasound Med 2014 Aug; 33(8):1393-400.
Owing to the fact that the potential frequency of endothelial dysfunction and early atherosclerosis might be higher in Behçet disease, characterized by acute and chronic inflammatory attacks, it may lead to impairment in flow-mediated dilatation and an increase in epicardial adipose tissue thickness. Therefore, we aimed to evaluate whether epicardial adipose tissue thickness and brachial artery flow-mediated dilatation as markers of early atherosclerosis and endothelial dysfunction were associated with Behçet disease.Thirty-five patients with Behçet disease and 35 healthy volunteers were included in this study. Epicardial adipose tissue was identified as an anechoic space between epicardial layers on 2-dimensional images, and its thickness was measured on the free wall of the right ventricle. Right brachial artery flow-mediated dilatation was assessed according to recent guidelines.Serum γ-glutamyl transferase (GGT) levels and epicardial adipose tissue thickness were significantly higher (P = .001; P < .001 respectively), whereas flow-mediated, endothelium-dependent dilatation was significantly lower in the Behçet disease group than controls (P < .001). There was a significant negative association between epicardial adipose tissue thickness and flow-mediated dilatation (P < .001). Epicardial adipose tissue thickness was also positively correlated with Behçet disease activity (P< .001), Behçet disease duration (P< .001), and waist circumference (P< .001). Flow-mediated dilatation was negatively correlated with GGT (P< .001), Behçet disease activity (P< .001), and age (P< .001). There was also a significant association between GGT and Behçet disease activity (P < .001).We found that epicardial adipose tissue thickness was significantly higher and flow-mediated dilatation was significantly lower in patients with Behçet disease than in controls. We suggest that identification of increased epicardial adipose tissue might aid in the diagnosis and treatment of possible coronary artery disease in patients with Behçet disease.