Real-time Compound imaging: Verbesserte Erkennbarkeit von Punktionsnadeln und Markierungsdrähten gegenüber Single-line- Ultraschall?

Localization Accuracy of Ultrasound-Actuated Needle with Color Doppler Imaging

An ultrasonic needle-actuating device for tissue biopsy and regional anaesthesia offers enhanced needle visibility with color Doppler imaging. However, its specific performance is not yet fully determined. This work investigated the influence on needle visibility of the insertion angle and drive voltage, as well as determined the accuracy and agreement of needle tip localization by comparing color Doppler measurements with paired photographic and B-mode ultrasound measurements. Needle tip accuracy measurements in a gelatin phantom gave a regression trend, where the slope of trend is 0.8808; coefficient of determination (R²) is 0.8877; bias is −0.50 mm; and the 95% limits of agreement are from −1.31 to 0.31 mm when comparing color Doppler with photographic measurements. When comparing the color Doppler with B-mode ultrasound measurements, the slope of the regression trend is 1.0179; R² is 0.9651; bias is −0.16 mm; and the 95% limits of agreement are from −1.935 to 1.605 mm. The results demonstrate the accuracy of this technique and its potential for application to biopsy and ultrasound guided regional anaesthesia.

Electrolytic echo enhancement: a novel method to make needles more reflective to ultrasound

INTRODUCTION

This study examines the effect of augmenting the ultrasound reflectivity of needles using a novel electrolytic echo enhancement method.

METHODS

Needles were connected by a lead to the negative terminal of a 4.5 V direct current source. A grounding pad, connected to the positive terminal, was positioned on the undersurface of an ex vivo ox liver phantom. During needle insertion into the liver, electrolysis was induced creating a layer of gas on the needle electrode.

RESULTS

Analysis of images showed a significant increase in needle brightness using electrolytic echo enhancement. Brightness was found to increase by a factor of ×3.6 compared with controls (P < 0.001).

CONCLUSION

Electrolytic echo enhancement has the potential to make ultrasound-guided procedures safer and quicker for patients and increase the confidence of operators in their ability to see the whole needle including its tip.

Precision imaging of focal liver lesions: comparison with conventional sonography in terms of image quality

OBJECTIVES

The purpose of this study was to compare the Precision Imaging sonographic technique (Toshiba Medical Systems Corporation, Tokyo, Japan) with conventional sonography of liver lesions in terms of lesion conspicuity, margin sharpness, overall image quality, and posterior enhancement.

METHODS

Sixty-nine focal liver lesions in 60 patients (age range, 14-76 years; mean age, 43 years) were prospectively evaluated. Each lesion was examined with Precision Imaging and conventional sonography. All images were reviewed and graded on a 3-point scale by 2 readers for lesion conspicuity, margin sharpness, and overall image quality. Posterior acoustic enhancement was also analyzed in cystic lesions. A Wilcoxon signed rank test was used for statistical comparisons of the techniques for all parameters.

RESULTS

Statistical analysis showed that for margin sharpness, lesion conspicuity, and overall image quality, Precision Imaging was superior to conventional sonography (P< .05). In addition, according to lesion types and dimensions, Precision Imaging was significantly superior to conventional sonography for all parameters. For posterior enhancement, there was no significant difference between Precision Imaging and conventional sonography (P ≥ .05).

CONCLUSIONS

In sonography of focal liver lesions, Precision Imaging provides better lesion conspicuity, better margin sharpness, and better overall image quality than conventional sonography. With respect to posterior enhancement of cystic lesions, Precision Imaging is not significantly different from conventional sonography. Precision Imaging may be used as a complementary method in the sonographic evaluation of focal liver lesions.

Accuracy of ultrasound-guided, large-core needle breast biopsy

Ultrasound-guided, large-core needle biopsy (US-LCNB) of suspicious breast lesions is acknowledged as less invasive and less expensive and less time consuming than surgical biopsy, and provides a histologic diagnosis with a comparable high degree. US-LCNB has been proven to help reduce the number of unnecessary surgeries for benign disease. Its limitations, however, are false-negative results and underestimation of disease. Thus, the demand for breast teams is to carefully adhere to the principles of triple assessment and imaging-histologic correlation, and follow-up of lesions with a specific benign histology after biopsy. Also, the acceptance of guidelines and rigorous quality controls help to reliably minimize the delay in the diagnosis of breast cancer in patients with false-negative biopsies. This paper aims to summarize the equipment and methods as well as the benefits and limitations of US-LCNB. Also, guidelines of quality assessment are suggested. Finally, recent developments which may help to overcome the limitations of US-LCNB will be discussed, i.e., directional vacuum-assisted biopsy (VAB), three-dimensional (3D) US-guided biopsy, as well as the use of tissue harmonic imaging (THI) and compound imaging (CI) during biopsy.

[Modern ultrasound diagnostics of deep vein thrombosis in lung embolism of unknown origin]

PURPOSE

We compared innovative ultrasound techniques such as tissue harmonic imaging (THI) and cross-beam technique with speckle reduction imaging (SRI) to conventional fundamental B scan in the diagnosis of deep vein thrombosis.

MATERIAL AND METHODS

We investigated a total number of 185 patients with clinical symptoms of acute vein thrombosis. We documented the thrombosis in the patients using multifrequency ultrasound probes (5-7 MHz, 6-9 MHz, 9-14 MHz, Logig 9, GE) and recorded ultrasound sequences in fundamental B scan, THI, and cross-beam technique with SRI (grade 2). Three blinded ultrasound investigators ranked the marking of the thrombosis in each of these image modalities and graded them with the numbers 5 = weak, 4 = moderate, 3 = satisfactory, 2 = good, and 1 = excellent. We calculated the median and a t-test for each of these image modalities.

RESULTS

We diagnosed 115 thromboses (62%) in 185 investigated patients. This group could be divided as follows: 11 patients (6%) with three-level thrombosis, 37 patients (20%) with two-level thrombosis, and 67 (36%) with one-level thrombosis. The one-level thrombosis group included five (3%) patients with muscle vein thromboses, seven (4%) cases of thrombophlebitis without involvement of the deep vein system, and three (2%) cases of thrombophlebitis with involvement of the deep vein system. The t-test for unconnected samples showed significant differences (p <0.05) in iliac veins and highly significant differences (p <0.001) in the veins of the lower extremity due to the superior capabilities for detection of thrombosis using the cross-beam technique with SRI compared to THI and the fundamental B scan.

CONCLUSION

The use of high-resolution linear ultrasound probes with the concomitant application of THI and cross-beam technique with SRI facilitates the diagnosis of deep vein thrombosis. The employment of these new ultrasound modalities is an advantage in distinguishing the veins from the surrounding tissue structures and helps in evaluating the compressibility of venous vessels.

Contribution of tissue harmonic imaging and frequency compound imaging in interventional breast sonography

OBJECTIVE

The purpose of this study was to retrospectively compare conventional imaging, frequency compound imaging (CI), and tissue harmonic imaging (THI) in interventional breast sonography.

METHODS

Institutional Review Board approval and patient informed consent were not required. The authors reviewed 104 sonographically guided breast procedures in 83 patients. For each biopsy, 4 images obtained with conventional imaging, frequency CI at 10 and 14 MHz (CI10 and CI14), and THI were graded independently by 2 radiologists for lesion conspicuity, needle conspicuity, lesion and needle conspicuity, and overall image quality. Frequency CI at 10 MHz, CI14, and THI were compared with conventional imaging. Different clinical scenarios (fatty versus glandular background, fine needle versus core needle, and oblique versus horizontal needle direction) were evaluated.

RESULTS

Statistical analysis showed that for overall image quality, CI10 was the best setting (odds ratios [OR], 3.67 and 7.48). For lesion conspicuity, CI14 (OR, 3.55) and THI (OR, 1.77) improved lesion visibility in a fatty background, whereas THI (OR, 0.26) was very limited in a glandular background. For needle conspicuity, no setting was better than conventional, whereas THI was the least valuable setting (OR, 0.011 and 0.049). For lesion and needle conspicuity, CI10 showed significantly better results than conventional for a dense background (P = .0268 and .4028; OR, 2.435 and 1.383) with 1 reviewer, whereas THI was the least valuable setting (OR, 0.014 and 0.042).

CONCLUSIONS

Conventional imaging provided the best assessment of lesion and needle conspicuity. Frequency compounding is a useful setting for dense breast and for fine-needle aspiration. Tissue harmonic imaging has a role in the visualization of a lesion against a fatty background but is of limited value in needle visualization.

Neue Techniken der Urosonographie

New sonographic techniques in urology, together with their principles of operation, will be presented. Together with the utilization of broadband ultrasound scanners and digital beam formers, leading to better spatial resolution and increased line density in ultrasound imaging, panorama sonography enables the outline of wide lateral regions independent of the width of the scanner. Spatial compound sonography achieves a comparatively better visualization of details in the b-mode image than has yet been available. The continuously improved 3-D, now leading to 4-D, techniques, which means real time capabilities, make the visualization of unrestricted imaging planes, which are not seen in conventional 2-D techniques, possible. The second harmonic imaging technique, including the special applications tissue harmonic imaging (THI) and contrast harmonic imaging (CHI), uses special ultrasound signal processing procedures for capturing and evaluating tissue hemoperfusion-here in combination with ultrasound contrast agents (UCA). Furthermore, microvascular imaging (MVI) enables the visualization of perfusion in tissues reaching the microcirculation regions. This leads to new possibilities for the assessment of pathological perfusion patterns, e.g. in andrology (perfusion of testicles) and uro-oncology (hyperperfusion of malignant regions).

Application of adaptive image processing technique to real-time spatial compound ultrasound imaging improves image quality

RATIONALE AND OBJECTIVES

To assess the impact of adaptive filter postprocessing on quality of ultrasound images.

METHODS

Ultrasound images acquired with real-time spatial compound imaging (SonoCT imaging) were subsequently processed with an adaptive real time algorithm (XRES imaging). Conventional and XRES-processed images from abdominal, pediatric or small parts ultrasound explorations were compared. The delineation of borders, tissue contrast, amount of noise, and overall image quality were evaluated.

RESULTS

Delineation of borders and tissue contrast were improved on all images (P < 0.05). The amount of noise was reduced (P < 0.05). The overall image quality was improved for abdominal, pediatric and small parts ultrasound explorations (P < 0.05). No image degradation was found.

CONCLUSIONS

Adaptive processing provided better image quality without loss of clinically useful information.

Improvement of sonographic needle visibility in cirrhotic livers during transjugular intrahepatic portosystemic stent-shunt procedures with use of real-time compound imaging

The visibility of a transjugular intrahepatic portosystemic stent-shunt (TIPS) puncture needle was assessed with use of real-time compound imaging and single-line ultrasonography (US). In vitro and in vivo, needle-tissue contrast was calculated. With an increasing angle of incidence, the decrease in needle visibility was more pronounced for single-line US than for compound imaging. At angles of incidence of more than 30 degrees, the needle was barely visible with either technique. Subjective evaluation during TIPS procedures in 10 patients proved that the needle tip was significantly better seen with compound imaging. Therefore, real-time compound imaging significantly improved contrast and subjective visibility of the needle.

[Transrectal ultrasound of the prostate. Current status and prospects]

In recent years the role of ultrasound in the diagnosis of prostate carcinoma has increased in importance. In view of the increasing incidence of prostate cancer, which is the most frequent malignant neoplasm in men, TRUS (transrectal ultrasound) is an important imaging method in the diagnosis of various prostate diseases. This paper provides a basic overview of physical and technical bases of TRUS investigation of the prostate. It concerns technical developments and modern techniques designed to improve its value in diagnosis. Impressive innovations in ultrasound equipment, particularly in the area of colour-coded Doppler sonography in association with microbubble-enhanced colour Doppler ultrasound, have given rise to justifiable hope of improvements in the early diagnosis of prostate cancer.

Real-time spatial compound imaging in breast ultrasound

To determine the role of real-time spatial compound imaging in breast ultrasound (US), 38 patients with a total of 50 benign changes (fibroadenomas, cysts, lactiferous duct dilatation) underwent both conventional B-mode US and real-time spatial compound imaging under standardized examination settings. Subsequently, images were reviewed independently by three readers experienced in breast US and evaluated according to a multistage scoring system with regard to the presence of artefacts, delineation of boundaries and depiction of internal structures. With significant reader concordance, real-time spatial compound imaging was found to produce speckle reduction with improvement of tissue differentiation, increased conspicuity of low-contrast lesions, enhanced delineation of capsular margins and ducts, and improved depiction of internal architecture of solid lesions, as well as clearer visualization of cystic contents due to clutter reduction. Preservation of central acoustic enhancement and lateral edge shadowing in cysts and fibroadenomas, however, was recorded better in conventional imaging.