Direct measurement of sound velocity in various specimens of breast tissue.

RATIONALE AND OBJECTIVES: Previous studies using ultrasound CT or clinical amplitude/velocity reconstruction imaging ultrasound may indicate that cancers differ from normal breast tissue by increased sound velocity. However, only limited experience with direct measurements of sound velocity exists. This study aimed to investigate sound velocity measured directly in a variety of breast specimens. METHODS: Sound velocity was measured directly by forceps in fresh breast specimens chosen to contain one type of tissue only. Eighty specimens (31 cancers, 18 benign changes of glandular/fibrous tissue, 22 fatty tissues, 5 fibroadenomas, 2 compound tissues, 1 phylloides tumor, and 1 inflammation) were analyzed. RESULTS: Ultrasound velocities in carcinoma, benign changes, fibroadenoma, inflammation, and the phylloides tumor were very similar, with almost complete overlap. In contrary, the ultrasound velocity of fatty tissue was significantly lower. Compound tissues containing fat had an intermediate sound velocity. CONCLUSIONS: Sound velocity may add complementary information to echogenicity (B-scan). Because fat lobules exhibit low ultrasound velocity and carcinomas do not, a locally exact combination of ultrasound velocity information and reflexivity information should allow improved breast cancer detection by ultrasound.

[Direct in-vitro measurement of ultrasound velocity in carcinomas, mastopathic tissue, fatty tissue and fibroadenomas of the female breast]. / Direkte In-vitro-Messung der Ultraschallgeschwindigkeit in Karzinomen, mastopathischem Gewebe, Fettgewebe und Fibroadenomen der weiblichen Brustdrüse.

PURPOSE: The study aimed to investigate ultrasound velocity (SV) in carcinomas, fibrocystic changes, fibroadenomas and fatty tissue of the female breast by means of direct in-vitro measurements. We intended to test whether or not differences in SV exist between the various types of tissue and whether the SV is a useful criterion to differentiate the different tissues. METHOD: SV was measured by comparing transmission time of the ultrasound beam through the specimen and through water. Altogether 40 specimens (12 cancer, 14 fibrocystic changes = FCD, 10 fatty tissues, 3 fibroadenomas, and 1 mixed tissue) were analysed. RESULTS: Velocity differed significantly between fat (1478.5 +/- 6.5 m/s) and tumor (1523.1 +/- 5.9 m/s) (p approximately 10(-11)) and between fat and FCD (1526.0 +/- 9.0 m/s) (p approximately 10(-12)). No significant differences and much overlap were seen between the ultrasound velocities of tumors and FCD. Ultrasound velocity in fibroadenomas (1533.2 +/- 3.8 m/s) was comparable with that in carcinomas and FCD. CONCLUSIONS: We conclude that ultrasound velocity may add complementary information to echogenicity (B-scan). Thus, a locally exact correlation of echogenicity and sound velocity might allow for an improved tissue characterization.

Stereotactic breast biopsies: analysis of needle deviation based on stereotactic views.

Stereotaxy is widely used for breast biopsy and needle localization of mammographically detected lesions. If a lesion shift occurs during stereotaxy, corrections (even though possible with vacuum biopsy) is difficult due to the difficult assessment of the exact 3D shift. In this study we investigated the correlation between lesion shift (in up to three dimensions) and its visualisation on the stereotactic images (0 degree, -15 degrees, +15 degrees). The study was performed on a Fischer prone table (Fischer Imaging Europe, Vejle, Denmark) using a 3.8-mm steel ball (as lesion) and a 20-G needle. The 17 major malpositions of the ball with respect to the needle were imitated and imaged. A simple rule is suggested as to how the deviation in all three dimensions can be detected from the scout and the two stereotactic views. The rule proved to be a valuable tool to correctly assess lesion shifts.

Sarcomere length-tension relationship of rat cardiac myocytes at lengths greater than optimum.

The study was aimed at determining both passive and Ca(2+)-activated forces of single skinned rat cardiac cells. Particular attention was paid to the descending limb of the active length-tension curve while the sarcomeric order of stretched cells was investigated before and during contraction. To analyse sarcomere length and sarcomere-length inhomogeneity, a fast Fourier transform (FFT) was employed. The fundamental frequency in the FFT spectrum is a measure of sarcomere length. The full-width-half-maximum of the first-order line is a measure of sarcomere-length inhomogeneity. In relaxing buffer, the sarcomere-length inhomogeneity of skinned cells increased linearly with mean sarcomere length. Upon Ca(2+)-dependent activation of skinned cells contracting isometrically, mean sarcomere length decreased slightly and inhomogeneity increased; both effects were greater at higher Ca(2+)concentrations. Maximum activation was reached at sarcomere lengths between 2.2 and 2.4 microm, whereas the descending limb of the active length-tension curve approached zero force already at approximately 2.8 microm. This steep force decline could not be explained by overly inhomogeneous sarcomere lengths in very long, contracting cells. Rather, the results of mechanical measurements on single cardiac myofibrils implied that high stretching is accompanied by irreversible structural alterations within cardiac sarcomeres, most likely thick-filament disarray and disruption of binding sites between myosin and titin due to changes in titin's tertiary structure. Loss of a regular thick-filament organization may then impair active force generation. We conclude that the descending limb of the cardiac length-tension curve is determined both by the degree of actin-myosin overlap and by the intrinsic properties of titin filaments.

[New knowledge regarding tumor cell inactivation and histological evaluation after radiofrequency therapy. Single case observation and in vitro proof of a new hypothesis]. / Neue Erkenntnisse über Tumorzellinaktivierung und histologische Beurteilbarkeit nach Radiofrequenztherapie. Einzelfallbeobachtung und In-vitro-Nachweis einer neuen Hypothese.

In a study, a radiofrequency (RF) treatment was performed on a patient with a small breast cancer after vacuum biopsy. As usual in cases with a malignant diagnosis, surgical excision and axillary dissection followed. Histopathology revealed some residual tumor in the margin of the cavity. It could not be distinguished from vital tumor on the hematotoxylin eosin (HE) stain. Based on the correlation of MRI and histopathology after subsequent surgical excision, we did, however, presume that the residual was contained within the zone of inactivation. Thus the hypothesis arose that, if too high temperatures can be avoided, it might be possible to inactivate tumor cells without significantly impairing histopathologic assessment. This hypothesis was supported by the following in vitro experiment performed on a fresh specimen: An RF treatment was performed using temperatures up to 70 degrees C only. Half of the specimen underwent HE-staining, the other half vitality testing. The results indicate that if a given temperature range is strictly observed it appears possible to inactivate tissue before tissue sampling, since histopathologic diagnosis will not be impaired. Further technologic improvements may eventually allow to develop a pre-treatment method which might permit to avoid potential hematogenous tumor spread during subsequent biopsy.