Whole-body imaging of oncologic patients using 16-channel PET-CT. Evaluation of an i.v. contrast enhanced MDCT protocol.

AIM: This study evaluated a MDCT protocol for contrast-enhanced 16-channel PET-CT with regard to scan range and duration of a whole-body (18)F-FDG PET-CT examination, the occurrence of contrast-material induced artefacts and quantitative assessment of CT attenuation. PATIENTS, METHODS: 205 patients (51.9+/-12.4 years) with different malignant tumours underwent whole-body PET-CT; the study protocol had been approved by the institutional review board. Contrast-enhanced MDCT (16 x 1.5 mm; 120 ml Iomeprol 3 ml/s, 50 ml saline chaser bolus, scan delay 70 s; oral contrast) was also used for attenuation correction. From MDCT data mean scan range and duration, occurrence of contrast media-induced artefacts, and mean CT densities of jugular (jv) and subclavian (scv), superior (vcs) and inferior (vci) caval, portal (pv), and bilateral external iliac veins, pulmonary (ap) and iliac arteries, descending thoracic and abdominal aorta, all cardiac chambers, as well as both liver lobes, spleen, adrenal glands and kidneys were determined. RESULTS: Attenuation corrected PET images were free of contrast media-related image artefacts. Homogeneous contrast enhancement was found in the mediastinal veins (right/left jv 171+/-34/171+/-35, scv 127+/-50/127+/-40, vcs 153+/-36 HU) and arteries (e.g. ap 145+/-26/151+/-26). Cardiac chambers, abdominal vessels (e.g. vci 138+/-24, pv 159+/-25 HU), and parenchymal organs revealed sufficient and homogenous contrast-enhancement in all cases. No beam-hardening artefacts occurred in the neighbourhood of the subclavian veins. CONCLUSION: The chosen whole-body (18)F-FDG 16-slice PET-CT protocol allowed for craniocaudal CT scanning with high vessel and parenchymal contrast revealing no IV contrast-media induced artefacts in attenuation-corrected PET data sets.

The glycocalyx and stereociliary interconnections of the vestibular sensory epithelia of the guinea pig. A freeze-fracture, low-voltage cryo-SEM, SEM and TEM study.

In this study freeze fracture, low-voltage cryo-SEM, SEM and TEM were used to characterise the glycocalyx and stereociliary interconnections in the hair cell bundle of the vestibular sensory epithelia of the guinea pig. The glycocalyx resembles a shell-like structure separately surrounding each stereocilium and kinocilium over its entire length. The lateral interciliary connections emerge from the glycocalyx layer, forming an extensive extracellular network maintaining the stereocilia as a bundle. These connections are morphologically similar to the glycocalyx, and grossly oriented in the same direction, indicative of a role in the mechanical transduction system. The matrix material around the glycocalyx also appears to be morphologically similar to the glycocalyx, suggesting the glycocalyx to be even more important in the mechanical transduction system. The tip-links are covered with a layer, which is a continuation of the glycocalyx covering the stereocilia.

The vestibular evoked response to linear, alternating, acceleration pulses without acoustic masking as a parameter of vestibular function.

In this study, short latency vestibular evoked potentials (VsEPs) were recorded in five guinea pigs in response to alternating linear acceleration pulses with and without acoustic masking. A steel bolt was implanted in the skull and coupled to a shaker. Linear acceleration pulses (n = 400) in upward, downward or alternating directions were given, with a peak acceleration of 4g after 0.5 msec. Tests were repeated with acoustic masking, after modiolus destruction and after application of KCl in the vestibule. Stimuli of the vestibular nerve were recorded with a platinum electrode in the bony facial nerve canal in the bulla. Unilateral linear acceleration showed a shallow plateau at 0.5 msec, which disappeared with alternating acceleration impulses and after modiolus destruction. Therefore all further tests were done with alternating impulses. After a latency time of 0.8 msec a multiwave response was seen, with a first positive peak P1 at 1.16 ms. These were followed by other positive and negative peaks (N1, P2, N2, P3, N3). With the elimination of cochlear influences by using acoustic masking, P1 remained stable, while subsequent peaks were altered or eliminated. After modiolus destruction, the P1 peak remained, although with a smaller amplitude due to vestibular damage. After application of a saturated KCl solution in the vestibule all responses, including P1, disappeared, thus confirming the vestibular origin of these responses. We conclude that the onset latency of the VsEP and the peak latency and level of the first positive peak P1 in response to alternating linear acceleration pulses without acoustic masking, measured in the facial canal, are good and stable parameters of vestibular function in guinea pigs.

Variability of serum gonadotropin and dehydroepiandrosterone sulfate concentrations in women with polycystic ovary syndrome.

This study was designed to assess the variability of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and dehydroepiandrosterone sulfate (DHEAS) levels over time in women with polycystic ovary syndrome (PCOS). Serum LH, FHS and DHEAS concentrations were determined for four consecutive monthly intervals in three groups of women: group 1, normal cycling women in the follicular phase (n = 9); group 2, normal cycling women in the luteal phase (n = 10); and group 3, women with PCOS (n = 11). For LH, DHEAS and the LH/FSH ratio, a histogram was constructed based on whether the subjects in each group had 0, 1, 2, 3 or 4 high values. In addition, the coefficient of variation (CV) for the four individual values of each hormone was determined for each subject to quantitatively assess the variability of measurement over time. Histographic analysis revealed that an elevated LH value or an elevated LH/FSH ratio in PCOS was inconsistent. For DHEAS, 9 of 11 PCOS subjects had either 0 (n = 7) or 4 (n = 2) high values, suggesting that such determinations are relatively consistent. We conclude that (1) isolated LH or LH/FSH measurements may not be sufficiently reproducible to be clinically useful despite evidence that LH values may be more stable in PCOS than in normal women and (2) a normal or high DHEAS value in PCOS is more likely to be consistently replicated, although the number of subjects studied limits the power of this conclusion.

A prospective, randomized study of pregnancy rates after transuterotubal and intrauterine insemination.

OBJECTIVE: To assess the relative efficacy, in terms of clinical pregnancy rates (PRs), of transuterotubal insemination versus the more traditional intrauterine insemination (IUI) procedure. DESIGN: Prospective, randomized, cross-over. SETTING: University-affiliated tertiary care center. PATIENTS: One hundred sixty infertile patients underwent 414 inseminations with or without controlled ovarian hyperstimulation. INTERVENTIONS: All patients were randomized in their initial cycle to transuterotubal insemination or IUI then crossed-over in subsequent cycles (n = 191 total cycles of transuterotubal insemination and n = 223 total cycles of IUI). Transuterotubal insemination was performed initially with ultrasound guidance, and then a tactile technique was used for the last 6 months of the study. MAIN OUTCOME MEASURES: Clinical PRs and complications after both insemination methods. RESULTS: The clinical PR per treatment cycle was 7% (13/191) after transuterotubal insemination and 7% (16/223) after IUI. The overall PR per patient was 18% (29/160). The incidence of ectopic pregnancy was 1 in 191 for transuterotubal insemination cycles and 0 in 223 for IUI cycles. Other complications included 3 vasovagal episodes with transuterotubal insemination and 1 with IUI. There was no clinical evidence of tubal infection, trauma, or perforation in either group. CONCLUSION: Transuterotubal insemination did not appear to be associated with a higher PR when compared with IUI in this study. The potential for increased risk from complications related to the more invasive tubal technique does not appear to justify its use presently.

The predictive value of a single, early human chorionic gonadotropin measurement and the influence of maternal age on pregnancy outcome in an infertile population.

A single early quantitative hCG measurement 16 to 18 days after timed insemination has prognostic value with regard to pregnancy outcome in an asymptomatic, infertile population. Further, there is a statistically significant difference in the predictive value for hCG levels in patients less than or equal to 35 years compared with patients greater than 35 years of age. Interestingly, the same age-dependent phenomenon was observed when analyzing the predictive value of sonographically detected fetal heart motion at 5 weeks post-ovulation. We suggest that any investigation on pregnancy outcome, or its prediction should consider the impact of maternal age as a potentially significant covariate.