Mean Echogenicity Research Articles

Ovarian stromal echogenicity in women with clomiphene citrate–sensitive and clomiphene citrate–resistant polycystic ovary syndrome

Objective: To compare stromal echogenicity in women with clomiphene citrate (CC)–sensitive and CC-resistant polycystic ovary syndrome (PCOS), and to compare stromal echogenicity before and after laparoscopic ovarian drilling in women with CC-resistant PCOS. Design: Prospective study. Setting: University teaching hospital. Patient(s): Twenty-two infertile women. Intervention(s): Transvaginal ultrasound examination and laparoscopic ovarian drilling. Main Outcome Measure(s): Ovarian stromal index (ratio of mean ovarian stromal echogenicity to mean echogenicity of the entire ovary). Result(s): The mean (±SD) ovarian stromal index was 1.26 ± 0.27 in the women with CC-sensitive PCOS and 1.22 ± 0.11 in the women with CC-resistant PCOS. The ovarian stromal index and ovarian volume of the women with CC-resistant PCOS before and after ovarian drilling were not significantly different. Conclusion(s): There was no difference in the stromal index and ovarian volume between women with CC-sensitive PCOS and women with CC-resistant PCOS. There was no overall difference in the stromal index and ovarian volume in women with CC-resistant PCOS before and after ovarian drilling.

Ovarian stromal echogenicity in women with normal and polycystic ovaries.

Since the widespread use of transvaginal ultrasound to diagnose polycystic ovary syndrome (PCOS), a cardinal feature has been shown to be the presence of a bright, highly echogenic stroma. This is usually assessed subjectively. The objective of this study was to determine whether ovarian stromal echogenicity when measured objectively actually differed between women with polycystic ovaries and those with normal ovaries. A total of 67 women underwent a detailed ultrasound assessment before considering assisted conception treatment. Ovarian morphology was assessed and total ovarian volume, stromal volume, peak stromal blood flow velocity and mean stromal echogenicity were measured. The stromal index (ratio of mean stromal echogenicity to mean echogenicity of the entire ovary) and total stromal echogenicity were also calculated. Ovarian volume, stromal volume, and stromal peak blood flow velocity were all significantly higher in ovaries from women with PCOS. There was no difference in the mean stromal echogenicity, although the stromal index was significantly greater in women with polycystic ovaries. The apparent subjective increase in stromal echogenicity in women with polycystic ovaries, as exemplified by the greater stromal index, is due to a combination of the increased volume of ovarian stroma and the significantly lower mean echogenicity of the entire ovary in these women.

Follow-up of Wilms’ tumour during pre-operative chemotherapy by qualitative and quantitative sonography

Objectives. Evaluation of textural changes in Wilms’ tumour during chemotherapy by qualitative and quantitative ultrasonography. Methods. Sonograms of Wilms’ tumours during chemotherapy were retrospectively evaluated ( N=33) and compared with histopathology. Textural changes were prospectively quantified ( N=6) by mean echogenicity (MEAN) and coefficient of variation (CV) of grey levels. Results. Interobserver agreement for volume measurements was strong and for follow-up of sonolucencies moderate. Chemotherapy caused significant volume reduction and two major patterns of change in sonolucencies were observed; either increase or no change. No relationship between sonolucencies and volume changes was present. Sonolucencies yielded an underestimation of necrosis ( P<0.001). Trends in MEAN and CV differed between patients. Conclusions. Volume was the most objective sonographic tumour response parameter. Changes in sonolucencies may provide additional information on tumour response. However, sonolucencies are not an accurate measure of total tumour necrosis. It was not possible to differentiate Wilms’ tumour chemotherapy responders from non-responders by MEAN and CV.

Ultrasonography as a method to determine tendon cross-sectional area

SUMMARY Ultrasonographic cross-sectional area (csa) measurements of equine superficial digital flexor (sdf) tendon were obtained to determine the feasibility of ultrasonography for csa measurement of tendon in vivo and in vitro. Ultrasonographic measurements were compared with a more traditional csa measurement method, ink-blot analysis. In addition, values for ultrasonographic sdf tendon mean echogenicity were obtained in vivo and in vitro. The left forelimb sdf tendons of 23 horses were evaluated ultrasonographically. Cross-sectional images were acquired at 4-cm intervals distal to the base of the accessory carpal bone (dacb) to the level of the proximal sesamoid bones while horses were standing squarely. After euthanasia, the left forelimbs were mounted in a materials testing system (mts) and loaded under tension to standing load. Ultrasonographic images were again acquired at the same locations. The ultrasonographic images were digitized, and values for ultrasonographic csa and mean echogenicity were obtained for each level. Immediately after mechanical testing, a 1-cm-thick transverse section of sdf tendon at 12 cm dacb was removed. Three ink blots were prepared from each end of the removed tendon section and digitized. The 6 csa values were averaged to generate a value for morphologic csa for each sdf tendon at 12 cm dacb. Standing ultrasonographic tendon csa at 12 cm dacb was consistently smallest (mean ± sd csa = 86 ± 11 mm2), followed by mts ultrasonographic csa (mean, 95 ± 12 mm2), ink-blot morphologic csa being largest (mean, 99 ± 15 mm2). Comparison of standing and mts ultrasonographic csa values at 12 cm dacb revealed a strong positive linear correlation between methods (R2 = 0.74, P = 0.001). Comparison of ink-blot csa at 12 cm dacb with standing and mts ultrasonographic csa revealed strong positive linear correlations (R2 = 0.64, P = 0.001 and R2 = 0.72, P = 0.001, respectively). For ultrasonographic mean echogenicity, standing values insignificantly exceeded mts values at each level. The authors conclude that ultrasonography is a useful technique for the noninvasive assessment of sdf tendon csa that can be applied in vivo and in vitro.

Effect of maturation and aging on material and ultrasonographic properties of equine superficial digital flexor tendon

SUMMARY Results of studies in human beings and other species have indicated that aging significantly influences the strength, modulus of elasticity, and energy storage ability of tendon. We wanted to determine the effects of aging on the material and ultrasonographic properties of equine superficial digital flexor (sdf) tendon. Ultrasonographic measurements of left forelimb sdf tendon cross-sectional area and mean echogenicity were made in 23 standing horses ranging in age from 2 to 23 years. All horses had not been in work for a minimum of 6 months prior to the study. After euthanasia, left forelimb bone-muscle-tendon-bone specimens were mounted in a materials testing system. The sdf tendon was cyclically loaded sinusoidally 100 times at 0.5 Hz from 1.5 to 5.0% strain, then was submitted to 10-minute creep-and-stress relaxation tests. Modulus of elasticity, load at 3% strain, and creep-and-stress relaxation were determined for each specimen. A significant positive correlation was found between elastic modulus and age. Correlation was not found between age and sdf tendon cross-sectional area or mean echogenicity. When 2-year-old horses were compared with older horses, the latter had tendons with a significantly (P = 0.007) greater modulus of elasticity. The authors conclude that increasing age through maturity is associated with a corresponding increase in equine sdf tendon elastic modulus.

Ultrasonographic cross-sectional area and mean echogenicity of the superficial and deep digital flexor tendons in 50 trained Thoroughbred racehorses

SUMMARY Fifty Thoroughbred horses were examined. All horses had been in race training for a minimum of 4 months before examination and had worked at racing speed; 24 horses had raced. All horses were clinically sound at the time of examination. Ultrasonography was performed, using a 7.5-MHz transducer with built-in fluid offset. Videotaped images of the palmar soft tissue structures were obtained at 4, 8, 12, 16, 20, and 24 cm distal to the base of the accessory carpal bone (dacb). Images were digitized, and each image was calibrated. Values for cross-sectional area (csa) and mean echogenicity (me) were then determined from the cross-sectional images of the superficial digital flexor (sdf) and the deep digital flexor (ddf) tendons, using an image-analysis program. The sdf tendons were compared between right and left forelimbs at each level, and from proximad to distad on each limb, as were the ddf tendons. The relation between the sdf and ddf tendons for the same forelimb was determined at each level. There were no significant differences in csa or me at equivalent levels of the left and right sdf tendons. Mean (± sd) csa was 1.01 (± 0.12) cm2 at 4 cm dacb, 0.95 (± 0.14) cm2 at 12 cm dacb, and 1.12 (± 0.15) cm2 at 24 cm dacb. Adjusted me was 2.34 (± 0.34) at 4 cm dacb, 2.03 (± 0.38) at 12 cm dacb, and 2.04 (± 0.35) at 24 cm dacb. The left and right ddf tendons did not have significant differences in csa or me at any level. Cross-sectional area was 1.13 (± 0.18) cm2 at 4 cm dacb, 1.01 (± 0.12) cm2 at 12 cm dacb, and 1.75 (± 0.29) cm2 at 24 cm dacb. Adjusted me was 2.60 (± 0.46) at 4 cm dacb, 2.49 (± 0.49) at 12 cm dacb, and 2.50 (± 0.44) at 24 cm dacb. At all levels, the left and right sdf tendons were smaller and less echoic than the ddf tendons of the same limb. The sdf and ddf tendons had an hourglass shape, with smallest csa at 12 cm dacb. Mean echogenicity generally decreased for the sdf and ddf tendons from proximad to distad on the limb. These results indicate that for clinically normal trained Thoroughbred racehorses, there should be no significant difference in csa or echogenicity between the left and right sdf tendons at equivalent distances dacb. There should be no significant differences in the left and right ddf tendons at equivalent levels dacb. The sdf tendon is usually smaller and less echoic than the corresponding ddf tendon at each level.

Letters to the editor

<h3>Abstract</h3> Achilles tendinopathy affects many running athletes and often leads to chronic pain and functional deficits. While changes in tendon structure have been linked with tendinopathy, the effects of distance running on tendon structure is not well understood. Therefore, the purpose of this study was to characterize structural differences in the Achilles tendons in healthy young adults and competitive distance runners using quantitative ultrasound analyses. We hypothesized that competitive distance runners with no clinical signs or symptoms of tendinopathy would have quantitative signs of tendon damage, characterized by decreased collagen alignment and echogenicity, in addition to previous reports of thicker tendons. Longitudinal ultrasound images of the right Achilles tendon mid-substance were acquired in competitive distance runners and recreationally-active adults. Collagen organization, mean echogenicity, and tendon thickness were quantified using image processing techniques. Clinical assessments confirmed that runners had no signs or symptoms of tendinopathy and controls were only included if they had no history of Achilles tendon pain or injuries. Runner tendons were 40% less organized, 48% thicker, and 41% less echogenic compared to the control tendons (p &lt; 0.001). Young adults engaged in competitive distance-running have structurally different tendons than recreationally-active young adults. While these structural differences have been associated with tendon damage, the lack of clinical symptoms of tendinopathy may suggest that these detected differences may either be precursors of tendinopathy development or protective adaptations to cyclic tendon loading experienced during running.

Ultrasonographically detected changes in equine superficial digital flexor tendons during the first months of race training

Summary The forefimb superficial digital flexor (sdf) tendons of 6 Thoroughbreds were examined clinically and ultrasonographically during the first 4 months of race training. Sonograms were interpreted clinically and by use of computer-aided analysis. Tendon tissue from all horses was examined histologically at the end of the study. Computer-aided analysis of sonograms of the sdf tendons revealed trends toward an increase in mean cross-sectional area and a decrease in mean echogenicity over time with training. An inverse relation was found between increase in cross-sectional area and decrease in mean echogenicity over time in training. Two of the trained horses developed clinical signs of mid sdf tendonitis. Ultrasonography revealed an increase in cross-sectional area and decrease in mean echogenicity of clinically affected areas of the sdf tendons of 1 horse, compared with changes observed prior to the onset of tendonitis (these changes were not statistically significant). Blood vessels and lymphatics supplying the clinically and ultrasonographically affected tendon sites were large and thick-walled. These changes were not observed in the tendons of the other horses at the end of the study. The authors conclude that equine sdf tendons adapt to the early months of race training by increasing in size and decreasing in echogencity, as determined by ultrasonography.

Enhancement of the echogenicity of flowing blood by the contrast agent perflubron.

Perflubron, or perfluorooctylbromide, is an effective ultrasound and computed tomography contrast agent in a lecithin emulsion form. The authors studied acoustical properties of perflubron emulsion in static human and flowing porcine blood for concentrations from 0% to 30% weight per volume. Propagation velocity (c), the intensity attenuation coefficient (mu), density (rho), and particle size were measured directly. Because the backscatter of flowing blood is dependent on shear rate, relative echogenicity was measured as a function of perflubron concentration in whole porcine blood, in a laminar flow system, at shear rates of 16.0 to 68.5 sec-1 for realtime sector scanner images obtained at 7.5 MHz. Neat perflubron is a colorless liquid with density of 1.93 g.mL-1 and velocity of 630 m.sec-1. The following values were obtained at 4.7 MHz in static human blood (hematocrit 44%) at expected human in vivo blood concentrations of 3.1% perflubron versus pure human blood: rho = 1.11 versus 1.05 g.mL-1, c = 1,480 versus 1,576 m.sec-1, mu = 1.00 versus 0.36 dB.cm-1. The mean echogenicity of whole porcine blood increased substantially with perflubron concentration and was inversely proportional to blood shear rate. Adding 3.1% concentration of perflubron increased image echogenicity at all shear rates studied, ranging from 70% at 68.5 sec-1 (16.3 cm.sec-1) up to 180% at 16.0 sec-1 (3.8 cm.sec-1). Perflubron enhancement of blood is marked and demonstrates shear rate dependence like that of whole blood.

The Effect of Naftidrofuryl on Red Blood Cell Aggregation Detected in vitro with Ultrasound

Red blood cell aggregates are mainly responsible for the echogenicity of flowing blood. Thus, ultrasound can be used to observe the degree of red blood cell aggregation in slow flow conditions. We quantified blood echogenicity to study aggregation tendency of red blood cells in blood of patients with claudication, patients with suspected venous thrombosis, and normal volunteers without and with in vitro addition of naftidrofuryl (10(-6) M). Normal volunteers showed lower original echogenicity than any group of patients, and claudication patients showed the highest echogenicity. Naftidrofuryl caused a fall in mean echogenicity in all groups, and its effect was pronounced on blood samples with a high original echogenicity.