Optimization of angular and frequency compounding in ultrasonic attenuation estimations

Abstract

Previous reports have shown that the variance in ultrasound attenuation measurements is reduced when spatial and frequency compounding were applied in data acquisition and analysis. This paper investigates factors affecting the efficiency of compound attenuation imaging methods. A theoretical expression is derived that predicts the correlation between attenuation versus frequency slope (beta) estimates as a function of the increment between measurement frequencies (deltaf ) and the angular separation between beam lines (Delta (theta)). Theoretical results are compared with those from attenuation measurements on tissue-mimicking phantoms and from simulation data. Both predictions and measurement results show that the correlation between beta estimates as a function of (Delta f ) is independent of the length of the radio frequency (rf) data segment over which beta is derived. However, it decreases with an increase in the length of the data segment used in power spectra estimates. In contrast, the correlation between beta estimates as a function of delta(theta) decreases when the rf data segment length is longer or the frequency of the signal is higher. O 2005 Acoustical Society of America.

Ultrasonic Attenuation Estimation in Small Plaque Samples Using a Power Difference Method

“…A com par i son of the at ten u a tion co ef fi cient es ti mated us ing the di rect fit and power dif fer ence meth ods for all the ex cised plaque spec i mens used in this study are shown in fig ure 8. 24 SHI ET AL…”

“…22 How ever, for ex-vivo mea sure ments, the ex cised plaque sam ples ob tained af ter ca rotid endarterectomy are usu ally very small, with di men sions of plaque tis sue be ing around 1-2 cm in length and 0.3-0.5 cm thick (plaque thick ness rep re sent tis sue from the in side ar tery wall to the plaque sur face). Sev eral meth ods used to es ti mate the at ten u a tion co ef fi cient described in the lit er a ture 23,24 re quire sam ple thick nesses around 0.5 to 1 cm to pro vide re li able es ti ma tion of the at ten u a tion co ef fi cient. How ever, in our ex-vivo ex per i ments, plaque thickness was usu ally around 0.3 to 0.5 cm.…”

“…In our lab o ra tory, Yao et al 22 pro posed the ref er ence phan tom method to re move sys tem de pend en cies and this method has been used to es ti mate sev eral prop er ties, such as at ten u a tion and back scat ter co ef fi cient. Tu et al 23,24 uti lized fre quency com pound ing and spa tial-an gu lar com pound ing to im prove the accu racy of at ten u a tion es ti ma tion. Lizzi et al 7 have also re lated their spec tral pa ram e ters, namely the slope and midband fit, to at ten u a tion, scat terer size, scat terer con cen tra tions and rel a tive acous tic im ped ance of tis sue scat ter ers.…”

Spatial Angular Compounding ofPhotoacoustic Images

“…The concept is similar to spatial compounding methods for improving the quality of US B-mode [10], [34]–[36], quantitative US [37], [38] and US strain [11], [39], [40] images. The success of spatial compounding of US images relies on the combination of fully decorrelated speckle patterns, which may be achieved with large relative translations [10] or rotations [41], deformation [26], or variations in transmit parameters, such as frequency [42] and beem steering [43].…”

Sonografische Mikrokalkdetektion – Potenzial einer neuen Methode

“…Folglich sollten neue sinnenphysiologisch optimierte Farbmappensysteme erarbeitet werden. Fischer et al konnten diese Ansätze der phototopischen Bildgebung bestätigen [18], welche Eingang in die ultraschallkontrastmittelspezifische Bildgebung gefunden haben [20]. Bis zum heutigen Zeitpunkt wurde in den Studien beim Vergleich zwischen Sonografie und Mammografie von bereits entweder mammografisch oder sonografisch detektierten Mikroverkalkungen ausgegangen [2, 3, 5, 6, 12, 21], wobei in den meisten Fällen das Mikrokalkareal gezielt untersucht wurde.…”