Examinando por Autor "Rominger, Martha B."

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    Ítem
    Comparison of ultrasound speed-of-sound of the lower extremity and lumbar muscle assessed with computed tomography for muscle loss assessment
    (Lippincott Williams and Wilkins, 2021-05-28) Ruby, Lisa; Sanabria Martín, Sergio José; Saltybaeva, Natalia; Frauenfelder, Thomas; Alkadhi, Hatem; Rominger, Martha B.
    To compare the speed of propagation of ultrasound (US) waves (SoS) of the lower leg with the clinical reference standard computed tomography (CT) at the level of lumbar vertebra 3 (L3) for muscle loss assessment. Both calf muscles of 50 patients scheduled for an abdominal CT were prospectively examined with ultrasound. A plexiglas-reflector located on the opposite side of the probe with the calf in between was used as a timing reference for SoS (m/s). CT measurements were performed at the level of L3 and included area (cm2) and attenuation (HU) of the psoas muscle, abdominal muscles, subcutaneous fat, visceral fat and abdominal area. Correlations between SoS, body mass index (BMI) and CT were determined using Pearson's correlation coefficient. Based on reported CT sarcopenia threshold values, receiver operating characteristic (ROC) analysis was performed for SoS. Inter-examiner agreement was assessed with the median difference, inter-quartile range (IQR) and intraclass correlation coefficients. SoS of the calf correlated moderately with abdominal muscle attenuation (r=0.48; P<.001), psoas muscle attenuation (r=0.40; P<.01), abdominal area (r=-0.44; P<.01) and weakly with subcutaneous fat area (r=-0.37; P<.01). BMI correlated weakly with psoas attenuation (r=-0.28; P<.05) and non-significantly with abdominal muscle attenuation. Normalization with abdominal area resulted in moderate correlations with abdominal muscle area for SoS (r=0.43; P<.01) and BMI (r=-0.46; P<.001). Based on sarcopenia threshold values for skeletal muscle attenuation (SMRA), area under curve (AUC) for SoS was 0.724. Median difference between both examiners was-3.4 m/s with IQR=15.1 m/s and intraclass correlation coefficient=0.794. SoS measurements of the calf are moderately accurate based on CT sarcopenia threshold values, thus showing potential for muscle loss quantification.
  • Miniatura
    Ítem
    Speed of sound and shear wave speed for calf soft tissue composition and nonlinearity assessment
    (AME Publishing Company, 2021-09) Korta Martiartu, Naiara; Nakhostin, Dominik; Ruby, Lisa; Frauenfelder, Thomas; Rominger, Martha B.; Sanabria Martín, Sergio José
    Background: The purpose of this study was threefold: (I) to study the correlation of speed-of-sound (SoS) and shear-wave-speed (SWS) ultrasound (US) in the gastrocnemius muscle, (II) to use reproducible tissue compression to characterize tissue nonlinearity effects, and (III) to compare the potential of SoS and SWS for tissue composition assessment. Methods: Twenty gastrocnemius muscles of 10 healthy young subjects (age range, 23–34 years, two females and eight males) were prospectively examined with both clinical SWS (GE Logiq E9, in m/s) and a prototype system that measures SoS (in m/s). A reflector was positioned opposite the US probe as a timing reference for SoS, with the muscle in between. Reproducible tissue compression was applied by reducing probe-reflector distance in 5 mm steps. The Ogden hyperelastic model and the acoustoelastic theory were used to characterize SoS and SWS variations with tissue compression and extract novel metrics related to tissue nonlinearity. The body fat percentage (BF%) of the subjects was estimated using bioelectrical impedance analysis. Results: A weak negative correlation was observed between SWS and SoS (r=−0.28, P=0.002). SWS showed an increasing trend with increasing tissue compression (P=0.10) while SoS values decayed nonlinearly (P<0.001). The acoustoelastic modeling showed a weak correlation for SWS (r=−0.36, P<0.001) but a very strong correlation for SoS (r=0.86, P<0.001), which was used to extract the SoS acoustoelastic parameter. SWS showed higher variability between both calves [intraclass correlation coefficient (ICC) =0.62, P=0.08] than SoS (ICC =0.91, P<0.001). Correlations with BF% were strong and positive for SWS (r=0.60, P<0.001), moderate and negative for SoS (r=−0.43, P=0.05), and moderate positive for SoS acoustoelastic parameter (r=0.48, P=0.03). Conclusions: SWS and SoS provide independent information about tissue elastic properties. SWS correlated stronger with BF% than SoS, but measurements were less reliable. SoS enabled the extraction of novel metrics related to tissue nonlinearity with potential complementary information.