Freehand Elasticity Imaging Using Speckle Decorrelation Rate

Bamber, Jeffrey C.; Bush, Nigel L.

doi:10.1007/978-1-4419-8772-3_45

Cited by 49 publications

(28 citation statements)

References 9 publications

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“…A range of image filtering and processing techniques can be applied. A freehand method of applying the compression has been tested [25,26] but using a motor-driven plate to ensure even compression [22,27] (e.g. using adapted mammography compressors) has been shown to give better results.…”

Section: Diagnostic Ultrasound Monitoringmentioning

confidence: 99%

Treatment monitoring and thermometry for therapeutic focused ultrasound

Rivens

Shaw

Civale

et al. 2007

International Journal of Hyperthermia

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Therapeutic ultrasound is currently enjoying increasingly widespread clinical use especially for the treatment of cancer of the prostate, liver, kidney, breast, pancreas and bone, as well as for the treatment of uterine fibroids. The optimum method of treatment delivery varies between anatomical sites, but in all cases monitoring of the treatment is crucial if extensive clinical acceptance is to be achieved. Monitoring not only provides the operating clinician with information relating to the effectiveness of treatment, but can also provide an early alert to the onset of adverse effects in normal tissue. This paper reviews invasive and non-invasive monitoring methods that have been applied to assess the extent of treatment during the delivery of therapeutic ultrasound in the laboratory and clinic (follow-up after treatment is not reviewed in detail). The monitoring of temperature and, importantly, the way in which this measurement can be used to estimate the delivered thermal dose, is dealt with as a separate special case. Already therapeutic ultrasound has reached a stage of development where it is possible to attempt real-time feedback during exposure in order to optimize each and every delivery of ultrasound energy. To date, data from MR imaging have shown better agreement with the size of regions of damage than those from diagnostic ultrasound, but novel ultrasonic techniques may redress this balance. Whilst MR currently offers the best method for non-invasive temperature measurement, the ultrasound techniques under development, which could potentially offer more rapid visualisation of results, are discussed.

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Section: Diagnostic Ultrasound Monitoringmentioning

confidence: 99%

Treatment monitoring and thermometry for therapeutic focused ultrasound

Rivens

Shaw

Civale

et al. 2007

International Journal of Hyperthermia

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show abstract

“…At the Institute of Cancer Research we have developed an elasticity imaging method that preserves and exploits this approach, which we believe should have widespread clinical impact even though it may be expected to suffer from more artefacts and yield poorer image quality than a mechanically constrained approach. Our early work demonstrated that hand-induced transducer motion can be a suitable method for applying the stress, but the displacement estimation method would have to cope with and perhaps correct for the effects of using relatively large displacements and unintended lateral and rotational probe motion [12]. Recent results have shown that the performance of freehand elastography, estimated using phantoms that provide an experimentally measured strain filter and Young's modulus stepresponse function, can approach that of mechanical elastography, although it is more variable [13].…”

Section: Freehand Elasticity Imagingmentioning

confidence: 99%

Ultrasound elasticity imaging: definition and technology

Bamber

1999

Eur Radiol

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“…Yet, in spite of its popularity, attested by thousands of clinical echocardiographic studies [8][9][10][11][12][13] over the last 10 years, translating STE into the daily clinical routine is far more challenging in both the single and multi-vendor clinical environments. Thus, though the Strain Standardization Initiative reduced significantly the inter-vendor variability of the strain measurements, a consequent study [14] concludes that current vendor independent STE software do and the sam Speckle tracking is mostly performed by block-matching [19][20][21][22] , where the displacement of a material point is estimated by searching for the "best match" between a block in the source frame and a block in the target frame. The center of the block in the source frame is usually defined as a "tracking point" (TP) [23] .…”

Section: Introductionmentioning

confidence: 99%

Feasibility of reproducible vendor independent estimation of cardiac function based on first generation speckle tracking echocardiography

Khamis

Shimoni

Hagendorff

et al. 2015

JBEI

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Background: The clinical approval of speckle tracking echocardiography (STE) as an accepted measure of myocardial strain and of LV function is hindered by the discordance of the results among the vendors. Since echocardiography images are noisy, the measured displacements are smoothed or regularized, an operation affecting the strain results. We introduce an "Error-dependent weighted speckle tracking" (EWST) algorithm that allows sensitivity analysis to the different operations affecting noise and accuracy. The aim here was to study whether by modifying the properties of the post block-matching weighted smoothing in the EWST algorithm it was possible to assess the expected inter-vendor strain differences. Methods and results:Forty-eight echocardiographic clips generated by a software-based phantom were used as "gold standard" for validation of the EWST algorithm. Also, a cohort of 435 normal subjects and a cohort of 47 patients, scanned/re-scanned at 2 frame-rates (~70; ~35), were studied using the EWST. The results were compared to those produced by a commercial product of a leading manufacturer (STE LV ). Peak global longitudinal strains [PRLS, (%)] and peak regional longitudinal strains [PRLS, (%)] were calculated and compared. Sensitivity to the region (ROI) determination was tested by shifting the apical endocardial boundary. The differences between the measured PGLS and the ground truth produced by the software-based phantom (average ± standard deviation) were 0.4% ± 0.6% and 1.0% ± 0.7% for the EWST and STE LV , respectively. Normal values were calculated for 435 subjects: -18.82% ± 2.45%, -20.2% ± 5.6%, -19.62% ± 3.62%, 18.77% ± 4.31% by the EWST, and -21.24% ± 2.91%, -26.5% ± 5.0%, -21.1% ± 3.7%, -18.0% ± 3.9%, by the STE LV , respectively, for the PGLS, the peak longitudinal apical, mid-ventricle and basal regions, respectively. A low bias, but significant, was found between PGLS, when calculated for the cohort of 47 patients scanned/re-scanned at 2 frame-rates: -0.80% ± 2.61% and -1.66% ± 2.66% for the EWST and STE LV , respectively. When the apex location (and thus the ROI) was shifted, the bias (mm) (average ± standard deviation) relative to the default position was: 0.82 ± 1.04; 0.61 ± 0.72; -1.06 ± 0.75; and -1.87 ± 0.72, for displacement of 5 cm, 2.5 cm, -2.5 cm, and -5 cm, respectively, for the STE LV . The EWST proved similarly sensitive to the shifting of the apex location. Conclusions: STE is sensitive to the characteristics and amount of smoothing, as well as to the ROI positioning. Modification of the smoothing can produce different stain results, and different distribution of the regional strains. Thus it is preferable to use automatic determination of the ROI and methods that employ minimal smoothing or regularization.

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Freehand Elasticity Imaging Using Speckle Decorrelation Rate

Cited by 49 publications

References 9 publications

Treatment monitoring and thermometry for therapeutic focused ultrasound

Treatment monitoring and thermometry for therapeutic focused ultrasound

Ultrasound elasticity imaging: definition and technology

Feasibility of reproducible vendor independent estimation of cardiac function based on first generation speckle tracking echocardiography

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