The Brief Neuropsychological Screening (BNS): valuation of its clinical validity.

The assessment of functional and cognitive efficiency of acute brain injured patients represents a relevant innovation in the rehabilitative approach to stroke patients. Indeed, the identification of severe cognitive difficulties early in the recovery process can be an important prognostic factor for the evolution of the disorders themselves. The aim of the present study was to describe a new diagnostic tool that rapidly assesses the cognitive efficiency of acute patients suffering from a cerebral vascular accident. The Brief Neuropsychological Screening (BNS) has been designed for the detection of either the presence or absence of damage in different cognitive areas, with particular emphasis to those most frequently occurring after a stroke, such as aphasia, apraxia, agnosia or eminattention. Data from 250 normal adult subjects and from a group of 150 acute cerebrovascular inpatients are also presented that confirm the validity of the BNS in discriminating acute patients affected by cognitive impairments from those free of cognitive disruption, and supports its prognostic value in predicting cognitive recovery over time.

Current status of intraoperative real-time vibrography in neurosurgery.

PURPOSE: Intracranial lesions are often characterized by different elasticities. The aim of the present study was to test the application of vibrography during brain tumor surgery. MATERIALS AND METHODS: The real-time vibrography system consisted of a conventional ultrasound system (Siemens Sonoline Omnia) with a custom-designed RF interface and a 6.5-MHz endocavity curved array (Siemens 6.5EC10). The RF data were digitized using a 50-MHz, 12-bit PCI analog/digital (A/D) converter for real-time or offline processing. Static compression was replaced by low-frequency axial vibration of the probe. A special applicator equipped with a stepping motor moved the ultrasonic probe and produced a low frequency mechanical vibration of 5-10 Hz with a vibration amplitude of 0.3 mm and slight preliminary compression (total<1 mm). The maximum application time was 60 sec. A pneumatic holding device (Unitrac, Aesculap, Tuttlingen, Germany) was used. RESULTS: Brain tissue is normally color coded between red and orange. In this study 41 out of 45 tumors could be detected via vibrography. Two tumors could not be detected with this imaging technique: a glioblastoma at a depth of 2 cm and a metastasis at a depth of 3 cm. Two additional tumors were not recognized because of technical problems. In 4 cases tumors with strain values identical to those in brain tissue (coded red or orange) but easily identified by a peripheral zone of high strain (yellow) were found. Tumors with strain values higher than those measured in brain tissue coded yellow and were softer than brain during surgical intervention. Higher strain was found in 23 tumors. Tumors with strain values lower than those in cerebral tissue were found to be harder during surgery and coded brown or black. Lower strain was found in 10 cases. Four tumors were inhomogeneous and could not be assigned to one of the above groups. Mortality was 0%, morbidity 2.3%. One patient displayed transient paresis of the lower extremity due to microsurgical difficulties during the approach. In one patient minimal bleeding of the cortical surface occurred in a frontobasal tumor; however, no postoperative deficits were noted. CONCLUSION: Vibrography is a new low-risk technique for intraoperative imaging. In low-grade astrocytomas and oligodendrogliomas, this additional technique can be used to control resection. In other cortical and subcortical tumors (e. g. metastases), it can provide an impression of the intratumoral elasticities.

[Prostate cancer diagnosis using ultrasound elastography. Introduction of a novel technique and first clinical results]. / Prostatakarzinomdiagnostik durch UltraschallelastographieVorstellung eines neuartigen Verfahrens und erste klinische Ergebnisse.

During the last decade screening has improved prostate cancer detection. The main reason for this development is a better understanding of the margins of prostate-specific antigen (PSA) serum levels and the classification of PSA subtypes. In contrast, the introduction of transrectal ultrasound has not led to a measurable change in the prostate cancer detection rate. Our aim was to develop a novel ultrasound system for the acquisition of elastographic images of the prostate and evaluate the system regarding its clinical applicability. We used a technically modified conventional ultrasound system and analyzed the high-frequency ultrasonic data with a computer program. The first patient-based results suggest that elastography allows an accurate measurement of tumor size and localization in contrast to conventional transrectal ultrasound. Elastography visualizes different tissue elasticities to distinguish benign and cancerous tissue. Thus, we were able to even correctly classify prostate cancer lesions which are iso- or hyperechoic in B-mode sonography.

New real-time strain imaging concepts using diagnostic ultrasound.

Two real-time strain imaging concepts and systems are presented. Both systems are based on a conventional ultrasound scanner that is connected to a PC with an A/D converter card for real-time data acquisition of rf data. Differential strain between successively acquired rf frames are estimated using phase root seeking. The first concept uses a special real-time implementation of manual elastography. In the second concept, denoted 'vibrography', the static compression is replaced by low-frequency axial vibration of the probe, still operating in quasistatic acquisition mode. The properties of both concepts are discussed with regard to noise and motion artefacts, and it is shown, using simulations and phantom experiments, that both imaging concepts yield the same kind of strain images. Vibrography has the advantage that no manual compression has to be applied, total compression can be very low and some motion artefacts are better suppressed.

A time-efficient and accurate strain estimation concept for ultrasonic elastography using iterative phase zero estimation.

In ultrasonic elastography, the exact estimation of temporal displacements between two signals is the key to estimating strain. An algorithm was previously proposed that estimates these displacements using phase differences of the corresponding base-band signals. A major advantage of these algorithms compared with correlation techniques is the computational efficiency. In this paper, an extension of the algorithm is presented that iteratively takes into account the time shifts of the signals to overcome the problems of aliasing and accuracy in the estimation of the phase shift. Thus, it can be proven that the algorithm is equivalent to the search of the maximum of the correlation function. Furthermore, a robust logarithmic compression is proposed that only compresses the envelope of the signal. This compression does not introduce systematic errors and significantly reduces decorrelation noise. The resulting algorithm is a computationally simple and very fast alternative to conventional correlation techniques, and the accuracy of strain images is improved.