No abstract

Real-time shear-wave elastography proved to be feasible in the assessment of testicular stiffness. It is important to consider the measurement region as standard values differ between the centre and the testicular periphery. Further studies with more subjects may be required to define the normal range of values for each age group. Useful clinical applications could include the diagnostic work-up of patients with scrotal masses or male infertility.

PURPOSE: Virtual touch tissue imaging quantification (VTIQ) is a newly developed technique for the sonographic quantification of tissue elasticity. It has been used in the assessment of breast lesions. The purpose of this study was to determine the diagnostic performance of VTIQ in indeterminate testicular lesions. METHODS: Twenty patients with known testicular pathology underwent conventional B-mode sonography with additional VTIQ of the testicular lesions using a Siemens Acuson S2000™ and S3000™ (Siemens Medical Solutions, Mountain View, CA, USA) system. Tissue mechanical properties were analysed in the VTIQ examination. The pathologic diagnosis was established after surgery or in the follow-up examination for suspected benign lesions. RESULTS: Over 36 months, 22 focal testicular lesions (median lesion size, 18 mm; range, 4-36 mm in 20 patients (median age, 43 years; range, 22-81 years) were examined. Lesions were hyperechoic (n = 1), hypoechoic (n = 14), isoechoic (n = 1), of mixed echogenicity (n = 3) or anechoic (n = 3). Histological examination showed one benign lesion (6.25%) with a mean size of 7 mm and 15 malignant lesions (93.75%) with a mean size of 20 mm. Mean shear wave velocity for normal testicular tissue was 1.17 m/s. No shear wave velocity could be measured in cystic lesions. The rest of the benign lesions showed a mean shear wave velocity of 2.37 m/s. The value of the shear wave velocity in germ cell tumours showed a mean shear wave velocity of 1.94 m/s and for seminoma it showed a mean shear wave velocity of 2.42 m/s. CONCLUSIONS: VTIQ is a reliable new method for measuring qualitative and quantitative stiffness of testicular lesions and tissue. The qualitative shear-wave elastography features were highly reproducible and showed good diagnostic performance in unclear testicular lesions. The VTIQ technique is also useful in assessing small testicular nodules and pseudolesions.

No abstract

Although histamine has been suggested to be involved in the control of male sexual function, including the induction of penile erection, its role in the human corpus cavernosum penis is still poorly understood. The aim of our study was to evaluate the course of histamine plasma levels through different stages of sexual arousal in the systemic and cavernous blood of healthy male subjects. Thirty four (34) healthy men were exposed to erotic stimuli to elicit penile erection. Blood was aspirated from the corpus cavernosum and a cubital vein during the penile conditions flaccidity, tumescence, rigidity and detumescence. Blood was also collected in the post-ejaculatory period. Plasma levels of histamine (ng ml(-1)) were determined by means of a radioimmunoassay. Histamine slightly decreased in the cavernous blood when the penis became tumescent. During rigidity, histamine decreased further but remained unaltered in the phase of detumescence and after ejaculation. In the systemic circulation, no alterations were observed with the initiation or termination of penile erection, whereas a significant drop was registered following ejaculation. Results are not in favour of the hypothesis of an excitatory role of histamine in the control of penile erection. Nevertheless, the amine might mediate biological events during the post-ejaculatory period.

3D SWE proved to be a feasible diagnostic tool in the assessment of testicular tissue, providing the examiner with a fully accessible three-dimensional map in a multiplanar or multislice view. With this technique a more precise testicular imaging - especially if combined with the display of tissue stiffness in SWE - is available and therefore could improve the diagnostic work-up of scrotal masses or the routine investigation of infertile men. Further studies for a better understanding in the context of various testicular pathologies will be required.

SSI values are significantly higher than ARFI values when measuring the stiffness of testicular tissue and should only be compared with caution.

Neuropeptide Y (NPY) has been shown to induce contraction of isolated human penile erectile tissue and potentiate the response to noradrenaline. The purpose of our study was to measure in the cavernous and systemic blood of healthy male volunteers the course of NPY through different stages of sexual arousal. Whole blood was drawn simultaneously from the corpus cavernosum and the cubital vein of 16 healthy male volunteers during penile flaccidity, tumescence, rigidity and detumescence. Tumescence and erection were induced by applying audiovisual and tactile stimulation. Plasma levels of NPY (given in pmol l(-1)) were determined by means of an enzyme-linked immunoassay. NPY significantly decreased in the cavernous blood on sexual arousal, when the flaccid penis became tumescent and, finally, rigid (F: 88.8 ± 35.8, T: 62.4 ± 22.7, R: 62.3 ± 19.7), and only slightly rose in the phase of detumescence (64.8 ± 23). In the systemic circulation, no pronounced alterations in the concentration of NPY were registered (F: 64.4 ± 27, T: 65.8 ± 19, R: 59.6 ± 25, D: 67.6 ± 29.3). Our findings are in favour of the hypothesis that NPY could contribute to the maintenance of the resting state of cavernous smooth muscle.