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Background Hidradenitis suppurativa is a chronic inflammatory skin disease. An ultrasound staging (SOS-HS) using frequencies from 7 to 18 MHz has been proposed to evaluate the severity of the disease. Materials and methods We retrospectively evaluated the most significant lesions in 50 patients with hidradenitis suppurativa (32 females and 18 males, aged from 12 to 68 years old), who had undergone high-frequency ultrasound (HFUS) (18-22 MHz) and ultra-high frequency ultrasound (UHFUS) (48 and 70 MHz). A MyLab™ Touch system (Esaote) equipped with a 18-22 MHz linear probe was used for the HFUS, and a Vevo® MD (VisualSonics) was used for the UHFUS, equipped with two linear probes (70 and 48 MHz). Results A total of 116 lesions were observed, of which 66 were fluid collections, 32 were tunnels, 6 pseudocysts, 5 bridge scars, 5 tombstone comedones, and 2 granulation tissues. Structures that had already been described with HFUS were then observed with UHFUS but with a better definition. In addition, structures that had not been detected by HFUS were also observed with UHFUS such as drop-shaped hair follicles, micro-tunnels, and microcysts. Conclusion Ultra-high frequency ultrasound provides a better understanding of hidradenitis suppurativa. Patients can be monitored more effectively thereby preventing the most severe changes.

An electrical resistance tomography (ERT) linear probe was used to measure gas hold-up in a two-phase (gas–liquid) and three phase (gas–solid–liquid) stirred-tank system equipped with a Rushton turbine. The ERT linear probe was chosen rather than the more commonly used ring cage geometry to achieve higher resolution in the axial direction as well as its potential for use on manufacturing plant. Gas-phase distribution was measured as a function of flow regime by varying both impeller speed and gas flow rate. Global and local gas hold-up values were calculated using ERT data by applying Maxwell's equation for conduction through heterogeneous media. The results were compared with correlations, hard-field tomography data, and computational fluid dynamic simulations available in the literature, showing good agreement. This study thus demonstrates the capability of ERT using a linear probe to offer, besides qualitative tomographic images, reliable quantitative data regarding phase distribution in gas–liquid systems.

Aim Superb microvascular imaging (SMI) is an ultrasound Doppler technique employing a unique algorithm that allows visualization of minute vessels with slow velocity and minimal motion artifacts. The aim of this preliminary study was to investigate whether SMI could predict liver fibrosis by visualizing the vessels present in the vicinity of the liver surface because the morphology of the peripheral hepatic vasculature is affected by the progression of liver fibrosis. Methods We recruited 29 patients with biopsy-proven chronic hepatitis C or liver cirrhosis C, and 36 patients without liver disease as controls. Using an Aplio 500 ultrasound system with a 7 MHz or 12 MHz linear probe, we assessed the vascular shapes and the bifurcation angles of 5 randomly selected vessels in the vicinity of the liver surface. The vascular shape was scored based on the number of winding and/or irregular vessels. Results The mean vascular score and the mean bifurcation angle were significantly greater in patients with advanced liver fibrosis (3.5 ± 1.1 and 90.5 ± 14.3) than in those with mild-to-moderate liver fibrosis (1.3 ± 1.4 and 68.0 ± 16.1) and controls (0.6 ± 0.7 and 62.2 ± 10.5), respectively. The area under the receiver-operator curve of the vascular score and the bifurcation angle were 0.88 with 76.5% sensitivity and 83.3% specificity, and 0.87 with 94.1% sensitivity and 75.0% specificity, respectively. Conclusion The present results indicate that SMI potentially predicts the extent of liver fibrosis by detecting small vessels present in the vicinity of the liver surface.

Introduction This study was undertaken to assess the intra-rater and inter-rater reliability of sonographic thickness measurements of the thenar and hypothenar muscles. Methods The thickness of the thenar and hypothenar muscles of both hands of 15 volunteers (7 male, 8 female) were evaluated with a 4- to 13- MHz linear probe by two examiners who were blinded to each other's measurements. Inter-rater reliability was then evaluated. To assess intra-rater reliability, the first examiner also performed a second measurement after an interval of at least one day. Results Mean age of the subjects was 31.1 ± 9.0 years. Test-retest reliability showed excellent intra-rater reliability (intraclass correlation coefficient range, 0.889-0.963) and substantial to excellent results for inter-rater reliability (intraclass correlation coefficient range, 0.692-0.937). Discussion We found that ultrasound is a reliable method for thickness measurements of the thenar and hypothenar muscles. This article is protected by copyright. All rights reserved.

Simultaneous recordings of multiple neuron activities with multi-channel extracellular electrodes are widely used for studying information processing by the brain's neural circuits. In this method, the recorded signals containing the spike events of a number of adjacent or distant neurons must be correctly sorted into spike trains of individual neurons, and a variety of methods have been proposed for this spike sorting. However, spike sorting is computationally difficult because the recorded signals are often contaminated by biological noise. Here, we propose a novel method for spike detection, which is the first stage of spike sorting and hence crucially determines overall sorting performance. Our method utilizes a model of extracellular recording data that takes into account variations in spike waveforms, such as the widths and amplitudes of spikes, by detecting the peaks of band-pass-filtered data. We show that the new method significantly improves the cost-performance of multi-channel electrode recordings by increasing the number of cleanly sorted neurons.

The surface anatomy of the saphenofemoral junction (SFJ) is especially relevant to surgeons. It is variably described in contemporary anatomy and clinical texts but is usually stated to lie 2.5-4 cm below and lateral to the pubic tubercle. The aim of this study was to map the SFJ accurately in healthy adults using ultrasound. One hundred healthy adults (mean age 27 years; 64 men) were scanned by an experienced sonographer using a 13-5 MHz linear probe. The center of the SFJ was recorded bilaterally in relation to the most superficial point of the pubic tubercle. The SFJ was readily identified in all participants. Its center was a mean of 2.4 ± 0.6 cm lateral (range 1-4.5 cm) and 1 ± 0.9 cm inferior to the pubic tubercle (range 2.5 above to 4 cm caudal to it). The junction was inferior to the pubic tubercle in 90% of lower limbs and at or above that level in 10%. In men, the SFJ was a mean of 2.6 cm lateral to the pubic tubercle and 1.2 cm inferior to it, compared with 2.2 and 0.6 cm, respectively, in women (P 90% of adults. The junction is slightly closer to the pubic tubercle in women. These results provide a more robust guide to the surface anatomy of the normal SFJ.

BACKGROUND AND PURPOSE Multipurpose ultrasound probes combined with ultra-mobile ultrasound instrumentation have the potential to increase the availability and use of ultrasound examinations in the assessment of atherosclerotic burden and cardiac disease. The aim of this study was to compare the agreement of a newly developed multipurpose probe to a standard linear carotid probe in detection of atherosclerosis of the precerebral arteries. METHODS We examined 103 patients with a multipurpose probe (General Electric, G9L MPP-9 MHz) and a standard linear probe (General Electric, Vivid 7-M12L-14 MHz). Measurements included intima-media thickness (IMT) in the common carotid arteries (CCA), carotid bifurcations (BIF), internal carotid arteries (ICA), and detection of carotid plaques and stenoses. RESULTS We found a significant level of agreement between the two probes for all IMT measurements with intraclass correlation coefficients (ICC) of: left CCA .91, left BIF .68, left ICA .75, right CCA .84, right BIF .74, and right ICA .59. Agreement with regard to carotid plaque and stenosis detection had kappa values of .94 and .93. CONCLUSION The multipurpose probe showed agreement with a standard linear probe in detecting atherosclerosis of the carotid arteries and has therefore the potential for use in both cardiac and precerebral ultrasound examinations.

Traditional current source density (tCSD) calculation method calculates neural current source distribution of extracellular (EC) potential patterns, thus providing important neurophysiological information. While the tCSD method is based on physical principles, it adopts some assumptions, which can not hold for single-cell activity. Consequently, tCSD method gives false results for single-cell activity. A new, spike CSD (sCSD) method has been developed, specifically designed to reveal CSD distribution of single cells during action potential generation. This method is based on the inverse solution of the Poisson-equation. The efficiency of the method is tested and demonstrated with simulations, and showed, that the sCSD method reconstructed the original CSD more precisely than the tCSD. The sCSD method is applied to EC spatial potential patterns of spikes, measured in cat primary auditory cortex with a 16-channel chronically implanted linear probe in vivo. Using our method, the cell–electrode distances were estimated and the spatio-temporal CSD distributions were reconstructed. The results suggested, that the new method is potentially useful in determining fine details of the spatio-temporal dynamics of spikes.

The continuity between the intercostal and paravertebral space has been established by several studies. In this study, the paravertebral spread of a colored dye was attempted with two different ultrasound-guided techniques. The posterior area of the trunk was scanned with a linear probe between the level of the fifth and the seventh thoracic vertebrae in eleven embalmed human cadavers. In the first technique, the probe was placed transversely below the inferior margin of the rib, and a needle was inserted between the internal intercostal membrane and the pleura. In the second technique, the probe was placed longitudinally at the intercostal space 5 cm lateral to the spinous processes, and the needle was inserted between the internal intercostal membrane and the pleura. In both techniques, 1 ml of methylene blue was injected, and both the intercostal and paravertebral spaces were prepared. In total, 33 injections were performed: 19 with the transverse technique and 14 with the longitudinal technique. Successful spread of the dye to the thoracic paravertebral space was recorded in 89.5% cases using the transverse technique and 92.8% cases using the longitudinal technique. No intrapleural spread of the dye was recorded in either technique. Ultrasound-guided injection into the intercostal space may offer an alternative approach to the thoracic paravertebral space.

BACKGROUND AND PURPOSE Due to the geometry of linear array transducers and the anatomy of the supraclavicular, and jugular fossa it is often impossible to get an appropriate ultrasonic view of the intrathoracic segments of the supraaortic arteries and their origin from the aortic arch. We aimed to compare a conventional linear with a microconvex array transducer for their ability to visualize these vessel segments. METHODS We examined 21 volunteers for the intrathoracic segments of the common carotid arteries (CCA), subclavian arteries (SA), vertebral arteries (VA), brachiocephalic (innominate) artery (IA), and the visibility of the aortic arch (AA) with a 5.7-10.0-MHz linear array and a 3.5-11.5-MHz microconvex array transducer. RESULTS The most proximal segment of the left CCA (0% vs. 47.6%, P= .0005), the left SA (0% vs. 23.8%, P= .0478), the left VA (47.6% vs. 90.5%, P= .0063), the IA (14.2% vs. 61.9%, P= .0036), and the AA (4.8% vs. 52.4%, P= .0014) were significantly more often visualized with the microconvex than with the linear probe. CONCLUSION Due to its much smaller contact surface, the microconvex array transducer revealed a better and more extended view of the intrathoracic segments of the supraaortic arteries and the aortic arch.

Background Pre-operative determination of primary melanoma thickness could be a tool to identify those patients who could be treated with radical primary tumour excision and sentinel lymph node biopsy in a single procedure. An excellent correlation between sonographic and histological measurement of maximal tumour thickness has been achieved using 20-MHz transducers. Objective To show that widely available high resolution ultrasound with 12–15 MHz linear probe could also reliably assess the thickness of primary melanoma. Methods Sixty-nine patients underwent ultrasound evaluation of 70 clinically and dermoscopically suspicious pigmented skin lesions before surgical excision. Results The sensitivity, specificity, positive and negative predictive values of ultrasound to detect melanoma > 1 mm were 92%, 92%, 95% and 81% respectively. The correlation between ultrasound and histological tumour thickness was very good [Pearson’s correlating index 0.823 (P 1 mm from those ≤ 1 mm.

Linear probe measurements are used to assess the severity and extent of attachment loss in chronic periodontitis and to identify, retrospectively, sites of disease activity. The use of the probe for these purposes is based on the implicit assumption that there is a direct and predictable relationship between linear probe measurements of attachment loss and the area of cemental surface which has been denuded of periodontal ligament. The aim of this study was to test this assumption by determining the correlation between loss of attachment as expressed by probe readings, and that expressed as the area of denuded root surface. The areas of denuded root surface of 236 teeth of different morphotype in 41 human dried skulls were determined by a rubber base impression technique and compared with their corresponding probe measurements, made at 10 sites per tooth. Although the majority of correlations between linear and area measurements were statistically significant for some individual morphotypes and categories of bone loss, there was overall, no consistent pattern of correlation between the two parameters. Furthermore, many correlations which were statistically significant had low values of the correlation coefficient: Kendall's T. It was concluded that probe readings are not a very precise measure of attachment loss, particularly with increasing severity destruction. These results cast doubt on the ability of individual linear measurements to represent the true severity of attachment loss, and thus on the precision of loss of attachment charts for retrospectively identifying sites of periodontal disease activity.