Echolocating horseshoe bats respond to flight-speed induced shifts in echo frequency by adjusting the frequency of subsequent calls. Under natural conditions, Doppler effects may force the frequency of a returning echo several kilohertz above the original emission frequency. By lowering subsequent call frequencies, the bat can return echo frequencies to within a narrow spectral bandwidth to whi...

The purpose of this study was to analyze the background parenchymal echotexture (BP echo) on breast ultrasound in detail and to evaluate the relation BP echo with menopausal status. In addition, we correlated BP echo with mammographic breast density (MGD) and background parenchymal enhancement (BPE) on magnetic resonance imaging (MRI).The institutional review board of our hospital approved this...

BACKGROUND AND PURPOSE In multiple sclerosis, gadolinium enhancement is used to classify lesions as active. Regarding the need for a standardized and accurate method for detection of multiple sclerosis activity, we compared 2D-spin-echo with 3D-gradient-echo T1WI for the detection of gadolinium-enhancing MS lesions. MATERIALS AND METHODS Fifty-eight patients with MS were prospectively imaged ...

Introduction: Two techniques have been presented in the last year to acquire both angiographic and venographic information in a single acquisition (MRAV) using susceptibility weighted imaging (SWI). One uses a double echo approach with the shorter echo used for the angiography and the longer echo used for the venography (1). The other uses a single echo that is a compromise between the two with...

Background: One of the most common causes of infertility in women is ovulatory dysfunction (PCOS) and the choice of treatment is clomiphene citrate. One of the mechanism of dichotomy between the rate of ovulation and pregnancy is anti estrogenic effects of clomiphene citrate on endometrium. According to its long half life, the anti estrogenic effects probably exacerbate in consecutive cycles. W...

PURPOSE To determine whether unenhanced high-resolution T2-weighted fast spin-echo MR imaging provides an acceptable and less expensive alternative to contrast-enhanced conventional T1-weighted spin-echo MR techniques in the diagnosis of acoustic schwannoma. METHODS We reviewed in a blinded fashion the records of 25 patients with pathologically documented acoustic schwannoma and of 25 control...