First clinical use of a standardized three-dimensional ultrasound for breast imaging.

OBJECTIVES: The feasibility, image quality, and diagnostic potential of the prototype of an automated ultrasound (US) breast scanner were examined. METHODS: Ninety-seven patients with suspicious breast lesions had mammograms, manual US, and an automated breast US. The data were evaluated according to the breast imaging reporting and data system (BIRADS) classification, image quality, and amount to diagnostic information. All lesions were confirmed histological. RESULTS: The image quality of the three-dimensional (3D) data sets was equal to or satisfactory compared with cross-sectional images from manual US in at least 72% of cases (p<0.05). The diagnostic information was equal or superior in at least 63% of cases (p<0.05). CONCLUSIONS: Standardized 3D US scanning is a promising diagnostic adjunct to mammography, but is no substitute for manual US at the current stage of development.

Analysis of 107 breast lesions with automated 3D ultrasound and comparison with mammography and manual ultrasound.

OBJECTIVES: Our aim was to investigate the diagnostic potential of an automated ultrasound (US) breast scanner prototype and compare it with manual US and mammography. METHODS: Ninety-seven patients with a total of 107 breast lesions had mammograms, manual US and an automated breast US scan. Multiplanar reconstructions in coronal, axial and the sagittal view were reconstructed from the automated dataset and visualized. After biopsy, all lesions were confirmed histologically. The data were evaluated according to the BIRADS (Breast Imaging Reporting and Data System) classification. The sensitivity and specificity were analyzed. RESULTS: The BIRADS criterion "margin" was significantly related to the overall BIRADS classification, independently of the US method being used. The sensitivity of mammography was significantly lower than of each US method (Fisher's exact test with p<0.05). There were no significant differences between the US methods. CONCLUSIONS: The reconstructed third (axial) image plane of the whole breast, which corresponds to a craniocaudal mammogram, can give additional information about both, site and differential diagnosis of a lesion. Although image quality was sufficient, automated US is not good enough to replace manual US at this time.

[3D ultrasound (3D US) in the diagnosis of focal breast lesions]. / 3D-Ultraschall (3D-US) in der Diagnostik von Mammaherdbefunden.

BACKGROUND: It was to analyse whether 3D breast US is able to enhance the diagnosis of focal breast lesions. MATERIAL AND METHODS: 60 patients were examined with 2D- and 3D US (GE logiq 9, 14 MHz). The solid lesions were analyzed by using the BIRADS classification. As standard of reference, histopathologic results were available in all cases. RESULTS: 38 malignant and 22 benign lesions were analyzed. With 2D US the sensitivity/specificity was 92/81%, with 3D US 97/72%, and by combination of 2D and 3D 97/81%. Characteristics of benign solid masses included a round or oval shape as well as clearly defined and sharply demarcated margins. CONCLUSIONS: 3D US allows to demonstrate breast masses in multiple planes. Distorsion of the surrounding soft tissues is an important sign indicative of malignancy.

Real-time detection of vessel diameters with ultrasound.

Transcutaneous vessel imaging is a frequently used ultrasound imaging modality in medicine. The measurement of vessel diameters can be done with conventional B-mode imaging systems, which work at frame rates up to 100 Hz. Furthermore, there are special systems available, which can track vessel walls very precisely using the phase of signals that are sent at frame rates up to several thousand Hz. Though, such systems are usually not able to provide the examiner with 2D images of the object. With respect to brachial artery flow-mediated vasodilatation (FMD), which is frequently used as a measure of endothelial function, it is necessary to observe diameter changes of small arterial vessels noninvasively for several minutes at a high resolution. In the past, the diameter had to be measured manually in tedious postprocessing of ECG-gated image sequences. We developed a system composed of a Siemens Omnia ultrasound system with a VF13-5 transducer (9 MHz center frequency) and a personal computer, that is capable of calculating vessel diameter changes with an accuracy below the wavelength of the ultrasound system in real-time at a frame rate of 27 Hz. We implemented a two-dimensional active contour model using the Viter-bi-algorithm and a phase-sensitive vessel wall tracking algorithm, in order to guarantee both, geometric information and accuracy. Results from carotid and brachial arteries show that arterial pulsations below 0.1 mm can be visualized reliably over several minutes. With this system we want to find out, if FMD is suitable for an individual assessment of the risk for cardiovascular diseases.

[Measurement of flow mediated vasodilation (FMD) using kalman-filtering]. / Measurement of flow mediated vasodilation (FMD) using kalman-filtering.

Brachial artery flow-mediated vasodilation is increasingly used as a measure of endothelial function. High resolution ultrasound provides a noninvasive method to observe this flow-mediated vasodilation by monitoring the diameter of the artery over time. In the past, the diameter had to be measured in tedious postprocessing routines, usually by the examiner himself. We present a system, which is able to process ultrasound rf-data in realtime. On that system, we implemented a kalman filter, which makes the tracking of both vessel walls possible. The diameter can be calculated accurately, taking into account process noise as well as measurement noise.

Freehand ultrasound elastography of breast lesions: clinical results.

We developed a freehand method for ultrasound elastography, which can be applied during a routine sonographic examination with off-line calculation of strain images (elastograms). Forty-eight patients with 53 breast lesions were examined and, after biopsy or operation, histologic reports were available for all lesions. The correlation coefficient of time delay estimates was used as a quality criterion for the subsequent calculation of elastograms. Beyond the qualitative evaluation of elastograms, we suggested a semiquantitative approach. For that purpose, the elastogram of each lesion was normalized to an overall strain of 1% (i.e., the average strain in the image was set to 1%). After normalization, we determined mean strain values inside and outside of each lesion, respectively. Defining solid lesions as benign and malignant lesions except for fibrous mastopathy, we found significant difference in strain between solid lesions and their surrounding tissue. However, that result must not be misunderstood to suggest that it was possible to distinguish benign from malignant lesions in general. Still, we address the potential of ultrasound elastography to improve the detection and localization of breast lesions as well as their differential diagnosis. Besides, we developed a freehand applicator for further studies, which guarantees a homogeneous axial compression regardless of the experience of the examiner.