Extended Field Of View Imaging Research Articles

Reliability of Muscle Quantity and Quality Measured With Extended-Field-of-View Ultrasound at Nine Body Sites

Measuring muscle quantity and quality is very important because the loss of muscle quantity and quality is associated with several adverse effects specifically in older people. Ultrasound is a method widely used to measure muscle quantity and quality. One problem with ultrasound is its limited field of view, which makes it impossible to measure the muscle quantity and quality of certain muscles. In this study, we aimed to evaluate the intra- and inter-rater reliability of extended-field-of-view (EFOV) ultrasound for the measurement of muscle quantity and quality in nine muscles of the limbs and trunk. Two examiners took two ultrasound EFOV images with a linear probe from each of the muscle sites. The intraclass correlation coefficient (ICC) was used, and the standard error of measurement and coefficient of variation were calculated. Intra-rater reliability was good to excellent (ICC=0.2-1.00) for all muscle measurements. The inter-rater reliability for most of the muscle measurements was good to excellent (ICC=0.82-0.98). Inter-rater reliability was moderate (0.58-0.72) for some muscle quantity measurements of the tibialis anterior, gastrocnemius, rectus femoris, biceps femoris and triceps brachii muscles. Muscle quantity and quality can be measured reliably using EFOV US.

Reliability and Comparison of Sonographic Methods for In Vivo Measurement of Human Biceps Femoris Long-Head Architecture.

Biceps femoris long-head fascicle length ( Lf ), fascicle angle (FA), and muscle thickness (MT) estimates obtained across 2 d from extended field-of-view (EFOV) sonographic images were compared with those measured from a collage of single ultrasound images (to visualize entire fascicles) as well as a range of geometric equations and extrapolation methods used on single images. Both test validity and intraday reliability were determined. Twenty healthy adults (10 men and 10 women) were tested on two occasions (day 1 and day 2), 7 d apart at the same time of day for test-retest measurements. Ultrasound imaging was performed using EFOV and static image acquisition sequences; in the latter, four single images were acquired in-series along the muscle. From these images, Lf was assessed using seven methods: EFOV, collage, manual linear extrapolation, and four different trigonometric equations (termed equations A, B, C, and D), and FA and MT were measured in EFOV, collage, and single images. Lf , FA, and MT measured on days 1 and 2 were not different ( P > 0.05) for any method, reliabilities were very high (intraclass correlation coefficient, 0.91-0.98), and correlations were strong (≥0.84). Significant correlations ( P < 0.05; r = 0.67-0.98) were found between EFOV and the other measurement techniques for Lf , FA, and MT. The collage method had the highest reliability for Lf , and highest rank order and correlation with EFOV. Although the six different techniques used to estimate Lf provided values similar to EFOV, higher between-subject measurement variability was observed with trigonometric equations, and the collage method described herein provided the most accurate and reliable results and is therefore recommended for biceps femoris long-head architectural analysis when EFOV is not available.

Assessment of computed tomography simulators used in radiotherapy treatment planning in Serbia, Croatia, and Bosnia and Herzegovina

The purpose of this work was to evaluate computed tomography simulators used in radio-therapy treatment planning in Serbia, Croatia, and Bosnia and Herzegovina. A survey of quality assurance programmes of 24 computed tomography simulators in 16 facilities was conducted. A dedicated CT-to-ED phantom was scanned at 120 kV and 140 kV, to obtain CT-to-ED conversion curves as well as CTDIvol. Thoracal phantoms were scanned in the standard and extended field of view to evaluate the dosimetric effect on treatment planning and delivery. The mean age of the measured scanners was 5.5 years. The mean water HU value was ?6.5 (all scanners, all voltages) and air HU value was ?997. Extended field of view computed tomography data differ from the standard field of view and differences between conversion curves have significant dosimetric impact. The CTDI data showed a large range of values between centers. Better quality assurance of computed tomography simulators in all countries is recommended. The CT-to-ED curve could be used as default at one voltage and per manufacturer. Extended field of view imaging can be used, but treatment planning should be avoided in the regions out of the standard field of view.

Stitching of 3D ultrasound datasets for the determination of large thyroid volumes - phantom study part II: mechanically-swept probes.

To investigate the feasibility and accuracy of 3D-US extended field of view volumetric analyses acquired with mechanically-swept ultrasound probes with different measurement methods for large volume thyroid phantoms. Fifteen thyroid phantoms with different shapes (regular, nodular, thickened isthmus) and volumes (50-400 mL) were created. Two different mechanically-swept US probes were used for the separate scanning of the left and right lobes: convex and linear probe. After specific modifications, the 3D-US datasets were stitched together to an extended field of view using predefined landmarks. Volumetric analyses were performed by conventional ellipsoid model and manual tracing methods. The correspondence of measured and reference volumes was calculated using Pearson's correlation coefficients and limits of agreement according to Bland and Altman. The C-probe proved feasible for the acquisition and processing of the three-dimensional ultrasound extended field of view images; very high levels of agreement (correlation coefficients for volume analyses: 0.9843-0.9992) were observed for all shapes and volumes investigated. The manual tracing method showed superior results in comparison to the ellipsoid model, but was more time consuming. The linear probe was only applicable for the 50 mL phantoms due to its limited field of view. The investigated mechanically-swept convex probe was suitable for the three-dimensional ultrasound extended field of view stitching of large volume thyroid phantoms. Accurate volume analyses could be carried out. The mechanically-swept linear probe is limited to a maximum of 50 m.

Ultrasound features of sole of foot pathology: a review.

Foot pain is a common problem among adults, with approximately 19% of men and 25% of women describing significant daily foot pain that limits their ability to function. Older adults, the obese, and active adults participating in sports involving running and jumping are at increased risk of developing pathology. Problems affecting the sole of the foot are often the cause of pain. Ultrasound is an extremely useful method of quickly and accurately localizing and characterizing pathology of the foot. The wide availability of ultrasound combined with its low cost, lack of ionizing radiation, high spatial resolution, multiplanar capability and excellent patient tolerance makes it an ideal technique for assessing the superficial structures in the sole of the foot. Ultrasound has the advantage of dynamic assessment over other imaging modalities. Furthermore, Doppler interrogation allows a real-time assessment of vascularity, not possible using other techniques. The ability to perform extended field of view images allows improved image presentation, which has increased clinicians’ acceptance of the technique. Finally, ultrasound can be used to guide interventional procedures. This review article will consider the ultrasound features of pathology commonly affecting the sole of the foot, and will describe MRI correlates that can be expected.

Assessing sarcopenia with vastus lateralis muscle ultrasound: an operative protocol.

Muscle ultrasound (MUS) has so far not been implemented for sarcopenia assessment in clinical geriatric practice due to allegedly low reproducibility of results in the absence of standardization of procedures. However, rigorous and standardized application of this technique yields highly reproducible results. Its application, especially if integrated with clinical evaluation and comprehensive geriatric assessment, proofs very useful for rapidly obtaining information on muscle mass and architecture. Here, we present a standardized protocol for performing right vastus lateralis (RVL) MUS and measuring parameters of muscle size and architecture. RVL muscle thickness (MT), fascicle length (FL), pennation angle (PA), echo-intensity (EI) and cross-sectional area (CSA) can be assessed with this protocol. A portable instrument equipped with a 5-cm long 3-11mHz linear probe should be used with both B-mode real-time and extended-field-of-view (EFOV) techniques. Longitudinal B-mode and transverse EFOV images should be acquired during each exam, and analyzed with NIH-ImageJ software. This operative protocol represents a good compromise between the feasibility of MUS in clinical settings and the need of obtaining precise measurements of muscle parameters. Future studies should verify the reproducibility of the proposed technique, and its correlation with appendicular lean mass and parameters of muscle function.

2.5-D Extended Field-of-View Ultrasound.

Recently, the growing emphasis on medical ultrasound (US) has led to a rapid development of US extended field-of-view (EFOV) techniques. US EFOV techniques can be classified into three categories: 2-D US EFOV, 3-D US, and 3-D US EFOV. In this paper, we propose a novel EFOV method called 2.5-D US EFOV that combines both the advantages of the 2-D US EFOV and the 3-D US by generating a panorama on a curved image plane guided by a curved scanning trajectory of the US probe. In 2.5-D US EFOV, the real-time position and orientation of the US image plane can be recorded via an electromagnetic spatial sensor attached to the probe. The scanning direction is not necessarily straight and can be curved according to the regions of interest (ROI). To form the curved panorama, an image cutting method is proposed. Finally, the curved panorama is rendered in a 3-D space using a surface rendering based on a texture mapping technique. This allows 3-D measurements of lines and angles. Phantom experiments demonstrated that 2.5-D US EFOV images could show anatomical structures of ROI accurately and rapidly. The overall average errors for the distance and angle measurements are -0.097 ± 0.128 cm (-1% ± 1.2%) and 1.50° ± 1.60° (1.9% ± 2%), respectively. A typical extended US image can be reconstructed from 321 B-scans images within 3 s. The satisfying quantitative result on the spinal tissues of a scoliosis subject demonstrates that our system has potential applications in the assessment of musculoskeletal issues.

Ultrasound measurements of Achilles tendon length using skin markings are more reliable than extended-field-of-view imaging.

Elongation of the Achilles tendon has been associated with poorer function in patients treated for ruptures. This has led to the development of various ultrasound-based measurements, and the purpose of the present study was to compare the reliability of three ultrasound-based measuring procedures. Twenty healthy individuals (40 tendons) were assessed by two testers at two occasions, 12 weeks apart. The tendon length was measured from the calcaneal insertion to the mid-sagittal muscle tendon junction (MTJ) using skin markings or extended-field-of-view (EFOV) imaging, or from the calcaneal insertion to the distal medial MTJ using skin markings. Test-retest and inter-tester reliability as well as side-to-side length differences were assessed for all three procedures. Test-retest intraclass correlation coefficients (ICCs) for measurements from the mid-sagittal MTJ using EFOV imaging and skin markings, and from the distal medial MTJ using skin markings were 0.83, 0.90 and 0.96 for tester 1 and 0.87, 0.91 and 0.96 for tester 2, respectively. The corresponding inter-tester ICCs were 0.85, 0.91 and 0.96. Side-to-side lengths were significantly different for measurements from the mid-sagittal MTJ and the distal medial MTJ using skin markings, with mean differences of 0.3 and 0.4cm, respectively. Test-retest and inter-tester ICCs were excellent for all three measuring procedures, however, the use of skin markings provided consistently better agreement and reliability compared to EFOV images. The best agreement and highest ICCs were achieved for measurements from the distal medial MTJ, but side-to-side length differences warrant caution when contralateral measurements are used to evaluate tendon elongation. III.

Real-time extended-field-of-view ultrasound based on a standard PC

Extended field-of-view (EFOV) can acquire a full field of vision, which can help doctors to make more objective and accurate diagnosis. Current EFOV techniques suffer from the low computation speed due to the large amount of ultrasound data to be processed. This paper describes an efficient technique to register 2D multiframe ultrasound images and produce EFOV images with significantly reduced computation time based on a standard PC. For registration of any two adjacent images, we propose to select less image blocks which are regarded as the most valid blocks based on the importance of image content. In registration of a sequence of images, with an assumption that the moving direction and speed of the probe are nearly identical during the data collection, we estimate the moving speed of the probe at the beginning of data collection and ignore redundant image data by processing a smaller number of frames according to a frame interval. The experimental results show that the computation speed of our method is increased by 7–80 times in comparison with two traditional methods, and can accurately produce EFOV images in real-time.

Does Extended-Field-of-View Sonography Improve Interrater Reliability for the Detection of Rotator Cuff Muscle Atrophy?

Assessment of rotator cuff muscle atrophy is an important component of the shoulder sonogram. We hypothesized that extended-field-of-view (EFOV) sonography would allow greater interrater reliability than conventional sonography for the evaluation of rotator cuff muscle atrophy. This retrospective study involved 50 consecutive patients who presented for shoulder sonography. All patients underwent EFOV imaging of the supraspinatus and infraspinatus muscles in addition to conventional imaging of each muscle. Five musculoskeletal radiologists first assessed 50 EFOV images of the supraspinatus and infraspinatus muscles and scored both muscles using a scale of 1-5. The reliability of each method was determined by calculating intraclass correlation coefficients (ICCs) according to a method developed by Shrout and Fleiss. The significance of the difference between reliabilities for conventional images and EFOV images was tested with a z-test. For the EFOV images, the ICC for the supraspinatus muscle was 0.77 and for the infraspinatus, 0.75. For the conventional images, the ICC for the supraspinatus muscle was 0.52 and for the infraspinatus, 0.57. The degree of interrater reliability for the five readers in our study was significantly higher for the EFOV images than for the conventional images (p < 0.0001). EFOV sonography results in greater interrater reliability than conventional sonography for the detection of rotator cuff muscle atrophy. EFOV images of the rotator cuff muscles should be obtained as part of routine shoulder sonography.

Multicontrast sequences with continuous table motion: A novel acquisition technique for extended field of view imaging

A novel acquisition technique called multicontrast imaging is presented that provides multiple datasets of different image contrasts covering an extended field of view within one measurement procedure. The technique uses a continuously moving table and is based on the repetitive acquisition of axial volume sections while the patient moves through the scanner once. To compensate for the table motion during the measurement, adaptive slice shifting is applied. Multicontrast imaging is designed to combine the comfort of a moving table examination with the high time efficiency of a multitask protocol and can be used for generating differences in both contrast and spatial parameters of the acquired data. The technique and its properties are demonstrated on healthy human volunteers.

Extended volume ultrasound data acquisition

Three or four-dimensional ultrasound data acquisition for extended field of view imaging is provided. Multiple volumes are registered with respect to each other and spliced together to form an extended volume. The extended volume is a contiguous volume larger than a volumetric region that a multi-dimensional or wobbler transducer array is capable of imaging without movement. Information representing different volumes is registered with respect to each other by sensing the transducer position associated with each of the different volumes. The position is sensed using a position sensing mechanism, such as magnetic optical or gyroscope measurements. Acoustic data may be used to determine decorrelation of speckle or correlation of features to sense position. After the volumes are registered, any overlapping regions are compounded. The resulting extended field of view volume is displayed and manipulated for viewing by the user. A large volume or extended volume of the patient is used for assessing an organ, such as an entire fetus in OB applications.

Advantages of and applications for extended field-of-view ultrasound in obstetrics

We evaluated the use of extended field-of-view (EFOV) ultrasound imaging in obstetrics and the possible advantages and applications. From July 2000 to May 2001, 57 randomly selected pregnancies and two woman postdelivery referred for routine and targeted ultrasound examination were studied by conventional B-mode and EFOV ultrasound. We subjectively compared conventional B-mode and EFOV by judging the general visualization as perceived by the operator and by the referring doctor. EFOV imaging provides better visualization of structures too large for a conventional sector image by creating one image of the entire structure and showing the relationship to or within the uterus. The EFOV images were easier to interpret by the referring or another nonexamining doctor. Fetal movements interfere with EFOV imaging, but not with the surrounding organs. A list of obstetrical applications for the use of EFOV is proposed. The use of EFOV imaging appears to be a reliable method to visualize the uterus in its entirety as well as genital tract tumors, the placental implantation and fetal structures throughout pregnancy. EFOV imaging of the fetus is limited by fetal movements.

3-D compound imaging with refraction and motion correction

The early goal of multiview imaging was delineation of quasi-specular image boundaries. Medical compound imaging was partially replaced because of resolution loss by refraction, misregistration, and tissue motion, and completely replaced due to incompatibility with real-time imaging. Three potential improvements in: boundary delineation, volumetric contrast-to-noise ratio, and Doppler anisotropy reduction (BC&amp;D) have remained an attraction of compounding. Now marketed, in-plane compounding in real-time and in extended field of view imaging offer the potential for in-plane, image-based reregistration of multiple views. Image volume-based registration (IVBaR) of separate angular views in 3-D data sets allows full 3-D displacement corrections. Compounding out of the image plane (elevational compounding) increases the number of independent views, increasing potential yield from improvements BC&amp;D. Our work has been in elevational compounding with conventional linear arrays, in contact with, and partially moving the proximal tissues. IVBaR using the mutual information metric and thin plate spline interpolation of warped volumes has produced exceptional reclamation of spatial resolution along with the expected improvements BC&amp;D. Full-volume, warped registration, and a faster, subvolume registration have been compared in vivo and with realistic beam aberrations in test objects. [Work supported in part by PHS Grant No. R01HL54201 from the NHLBI.]

SieScape panorama imaging in radiologic diagnosis

Through high-performance computer processing it has become possible to realize a new ultrasound imaging process: SieScape imaging. This method provides extended field of view images in real time using successive ultrasound images obtained when a standard transducer is scanned over a distance of up to 60 cm without any position sensor. SieScape offers new possibilities to view topographical anatomy. It is especially advantageous for scanning extended and tubular structures as well as large and enlarged organs and big pathologic volumes. Parallel scanning sequences allow documentation comparable to that of computed tomography. In addition, just as in magnetic resonance, variable imaging planes can be realized. The following describes the results obtained with SieScape in a multitude of clinical applications, especially in examinations of throat, thoracic and abdominal walls, breast, and intraabdominal organs as well as the soft tissues and small vessels of the extremities. The experience gathered with SieScape imaging--its advantages as well as its potential limitations, such as the formation of artefacts--is described.