Computed diffusion-weighted MRI for prostate cancer detection: the influence of the combinations of b-values

OBJECTIVE

To evaluate the influence of the combinations of b-values on computed diffusion-weighted images (cDWIs) for prostate cancer (PCa) detection at b = 2000 s mm(-2).

METHODS

Diffusion-weighted imaging (DWIs) for 31 patients with PCa (65.2 ± 7.1 years) were obtained pre-operatively at different b-values (0, 100, 500, 1000 and 2000 s mm(-2)) on a 3-T MRI. cDWIs at b = 2000 were generated by using six b-value combinations: 0-100 s mm(-2) (cDWI0-100); 0-500 s mm(-2) (cDWI0-500); 100-500 s mm(-2) (cDWI100-500); 0-1000 s mm(-2) (cDWI0-1000); 100-1000 s mm(-2) (cDWI100-1000); and 500-1000 s mm(-2) (cDWI500-1000). These cDWIs and measured DWIs with b = 2000 s mm(-2) (mDWI2000) were evaluated in this setting. To assess image quality for each DWI, contrast ratios (CRs) of cancerous and non-cancerous lesions were evaluated. To compare the detectability of PCa for each DWI, receiver operating characteristic analysis was used.

RESULTS

CRs of all cDWIs were significantly higher than those of mDWI2000 (p < 0.05). Areas under the curve of cDWI0-100 (0.62) and cDWI0-500 (0.65) were significantly smaller (p < 0.05) than those of others (cDWI100-500, 0.72; cDWI0-1000, 0.73; cDWI100-1000, 0.71; cDWI500-1000, 0.74; mDWI2000, 0.72).

CONCLUSION

The combinations of b-values influenced image quality and diagnostic ability of cDWIs for PCa detection. The combinations of b ≥ 100 and b ≥ 500 s mm(-2), as well as b = 0 and b = 1000 s mm(-2), were optimal in this study.

ADVANCES IN KNOWLEDGE

For generating the useful cDWI for PCa detection, radiologists should take care of the combination of b-values when including low b-values.

A prospective study of the incidence and outcomes of incidental dural tears in microendoscopic lumbar decompressive surgery

Little information is available about the incidence and outcome of incidental dural tears associated with microendoscopic lumbar decompressive surgery. We prospectively examined the incidence of dural tears and their influence on the outcome six months post-operatively in 555 consecutive patients (mean age 47.4 years (13 to 89)) who underwent this form of surgery. The incidence of dural tears was 5.05% (28/555). The risk factors were the age of the patient and the procedure of bilateral decompression via a unilateral approach. The rate of recovery of the Japanese Orthopaedic Association score in patients with dural tears was significantly lower than that in those without a tear (77.7% vs 87.6%; p < 0.02), although there were no significant differences in the improvement of the Oswestry Disability Index between the two groups. Most dural tears were small, managed by taking adequate care of symptoms of low cerebrospinal fluid pressure, and did not require direct dural repair. Routine MRI scans were undertaken six months post-operatively; four patients with a dural tear had recurrent or residual disc herniation and two had further stenosis, possibly because the dural tear prevented adequate decompression and removal of the fragments of disc during surgery; as yet, none of these patients have undergone further surgery.

Cite this article: Bone Joint J 2014;96-B:641–5.

The Effects of the Chemical and Radiolytic Degradation of Asphalt on Plutonium Solubility

The influence of alkaline degradation or radiolytic degradation of asphalt on plutonium solubility has been investigated. Asphalt has been contacted with water, sodium hydroxide solution or concrete leachate at 80°C for periods of up to approximately 2 years. Sodium nitrate was also present in some of the experiments. Plutonium solubilities were measured at pH 12 in the leachates and found to be less than 10-8 mol dm-3 for most degradations. Relatively low levels of Total Organic Carbon were measured in the leachates. Alpha radiolysis of asphalt in the presence of concrete and water has also been studied. Samples of asphalt were encapsulated in concrete after coating with the 238PuO2, crushed and leached at room temperature. The solubility of plutonium was measured in samples of the leachates after approximately 90 days and 180 days had elapsed. The results showed that the solubility of plutonium in the α-radiolysis leachates remained low and was in the range 2 × 10-11 to 8 × 10-9 mol dm-3. A consideration of these results, and data published elsewhere, suggests that chemical and radiolytic attack on asphalt or bitumen under anaerobic, alkaline conditions typical of a deep cementitious repository is unlikely to generate complexants for plutonium which are effective at high pH. Any enhancement of plutonium solubility is likely to be less significant than that arising from the degradation of some other organic materials.

The natural history of asymptomatic lumbar canal stenosis in patients undergoing surgery for cervical myelopathy

We retrospectively examined the prevalence and natural history of asymptomatic lumbar canal stenosis in patients treated surgically for cervical compressive myelopathy in order to assess the influence of latent lumbar canal stenosis on the recovery after surgery. Of 214 patients who had undergone cervical laminoplasty for cervical myelopathy, we identified 69 (32%) with myelographically documented lumbar canal stenosis. Of these, 28 (13%) patients with symptomatic lumbar canal stenosis underwent simultaneous cervical and lumbar decompression. Of the remaining 41 (19%) patients with asymptomatic lumbar canal stenosis who underwent only cervical surgery, 39 were followed up for ≥ 1 year (mean 4.9 years (1 to 12)) and were included in the analysis (study group). Patients without myelographic evidence of lumbar canal stenosis, who had been followed up for ≥ 1 year after the cervical surgery, served as controls (135 patients; mean follow-up period 6.5 years (1 to 17)). Among the 39 patients with asymptomatic lumbar canal stenosis, seven had lumbar-related leg symptoms after the cervical surgery.

Kaplan–Meier analysis showed that 89.6% (95% confidence interval (CI) 75.3 to 96.0) and 76.7% (95% CI 53.7 to 90.3) of the patients with asymptomatic lumbar canal stenosis were free from leg symptoms for three and five years, respectively. There were no significant differences between the study and control groups in the recovery rate measured by the Japanese Orthopaedic Association score or improvement in the Nurick score at one year after surgery or at the final follow-up.

These results suggest that latent lumbar canal stenosis does not influence recovery following surgery for cervical myelopathy; moreover, prophylactic lumbar decompression does not appear to be warranted as a routine procedure for coexistent asymptomatic lumbar canal stenosis in patients with cervical myelopathy, when planning cervical surgery.

Experimental Indications of Effects of Surface Deprotonation on Na-Bentonite Porewater Chemistry in a Geological Repository

Bentonite-water interaction was studied using a simple equilibrium model based on experimental measurements in order to describe bentonite porewater chemistry. Direct pH measurements for highly compacted bentonite and batch-type bentonite-water interaction experiments were performed under anaerobic conditions. In the direct pH measurements, resin particles doped with a pH indicator were sandwiched between a pair of bentonite columns immersed in a test solution. The experimental results showed that the solution compositions in equilibrium with bentonite depended on the bentonite to liquid ratio (B/L) and the initial solution composition. An equilibrium model assuming only fast equilibration processes between the bentonite minerals and the solution could be used to calculate the trends of pH and other ion concentrations with B/L. This study indicates that the surface deprotonation of smectite is a very important factor influencing the porewater chemistry in highly compacted bentonite.

Thermodynamics and solubility of (U x Np1- x )O2(am) solid solution in the carbonate system

The formation of a solid solution can significantly affect the solubility of a minor component. The objectives of this study were to determine the nature of U(IV) and Np(IV) solid solutions and their thermodynamic properties. For this purpose, (U x Np1- x )O2(am) precipitates with values of x varying from 0.05 to 0.95 were prepared, characterized, and used to determine their solubility in dilute to concentrated K2CO3 and KHCO3 solutions. The solubility data show that the equilibrium in these systems is reached in < 7 days, the solubility-controlling solids are amorphous, and that we were successful in maintaining U and Np in the tetravalent state. A scanning electron microscope equipped with energy dispersive spectrometry and X-ray absorption spectroscopic analyses of the solids indicated the quilibrated co-precipitates to be solid solutions. A close agreement between the thermodynamic predictions, assuming an ideal solid solution, and the experimental solubilities shows that U(IV) and Np(IV) form an ideal solid solution and that non-ideal solid solution behavior for this system can be ruled out.

Resistant starch and starch pasting properties of a starch synthase IIa-deficient wheat with apparent high amylose

The bread wheat (Triticum aestivum L.) analysed in this study has been produced by genetically eliminating the starch synthase IIa and shows apparent high amylose (HA) in the flour starch. Some starch properties of the HA wheat were analysed. The HA wheat contained 2.8–3.6% resistant starch (RS), much more than the normal (control) wheat, which contained almost no RS. Autoclaving the HA and normal wheat starches increased RS. The former contained 10.5% RS and the latter 5.9 or 6.8% RS. Swelling of the HA wheat starch and its pasting properties using Rapid ViscoAnalyzer (RVA) were investigated. Swelling power (g/g) of the HA wheat in 0.1% AgNO3 and swelling volume (mL/g) in urea solution were significantly less than those of the normal wheat. The RVA profile of the HA wholemeal and starch also differed from the normal. The peak viscosity, minimum viscosity, and final viscosity of HA were low, and breakdown (peak minus minimum viscosity) was very small. These findings show that amount of resistant starch and pasting properties are unique in the HA wheat starch, probably caused by lack of starch synthase IIa.

[Scimitar syndrome; report of a case]

A 17-year-old woman with scimitar syndrome without an atrial septal defect was operated by intra-cardiac conduit repair. Computed tomography (CT) and magnetic resonance imaging (MRI) showed resolution images of anatomical findings of scimitar vein. Surgical procedures for the scimitar syndrome have varied according to the anatomic features presented in each case. The detection of precise anatomy of scimitar syndrome is important for determining the appropriate surgical procedure. Images of 3-dimensional (3-D) CT and MRI of scimitar syndrome were demonstrated.

Experimental and modeling studies on sorption and diffusion of radium in bentonite

The sorption and desorption behavior of radium on bentonite and purified smectite was investigated as a function of pH, ionic strength and liquid to solid ratio by batch experiments. The distribution coefficients (Kd) were in the range of 10(2) to > 10(4) ml g-1 and depended on ionic strength and pH. Most of sorbed Ra was desorbed by 1 M KCl. The results for purified smectite indicated that Ra sorption is dominated by ion exchange at layer sites of smectite, and surface complexation at edge sites may increase Ra sorption at higher pH region. Reaction parameters between Ra and smectite were determined based on an interaction model between smectite and groundwater. The reaction parameters were then used to explain the results of bentonite by considering dissolution and precipitation of minerals and soluble impurities. The dependencies of experimental Kd values on pH, ionic strength and liquid to solid ratio were qualitatively explained by the model. The modeling result for bentonite indicated that sorption of Ra on bentonite is dominated by ion exchange with smectite. The observed pH dependency was caused by changes of Ca concentration arising from dissolution and precipitation of calcite. Diffusion behavior of Ra in bentonite was also investigated as a function of dry density and ionic strength. The apparent diffusion coefficients (Da) obtained in compacted bentonite were in the range of 1.1 x 10(-11) to 2.2 x 10(-12) m2 s-1 and decreased with increasing in dry density and ionic strength. The Kd values obtained by measured effective diffusion coefficient (De) and modeled De were consistent with those by the sorption model in a deviation within one order of magnitude.

An integrated sorption-diffusion model for the calculation of consistent distribution and diffusion coefficients in compacted bentonite

A thermodynamic sorption model and a diffusion model based on electric double layer (EDL) theory are integrated to yield a surface chemical model that treats porewater chemistry, surface reactions, and the influence of charged pore walls on diffusing ions in a consistent fashion. The relative contribution of Stern and diffuse layer to the compensation of the permanent surface charge represents a key parameter; it is optimized for the diffusion of Cs in Kunipia-F bentonite, at a dry density of 400 kg/m3. The model is then directly used to predict apparent diffusivities (Da) of Cs, Sr, Cl-, I- and TcO4- and corresponding distribution coefficients (Kd) of Cs and Sr in different bentonites as a function of dry density, without any further adjustment of surface chemical and EDL parameters. Effective diffusivities (De) for Cs, HTO, and TcO4- are also calculated. All calculated values (Da, De, Kd) are fully consistent with each other. A comparison with published, measured data shows that the present model allows a good prediction and consistent explanation of (i) apparent and effective diffusivities for cations, anions, and neutral species in compacted bentonite, and of (ii) Kd values in batch and compacted systems.

Speed congenics: a classic technique in the fast lane (relatively speaking)

Marker-assisted selection protocol (MASP)-based strategies produce congenic strains with the target gene contained on clearly defined donor-derived genomic intervals in less than half the member of generations required by the classic protocol. Thus, the quality and speed of congenic strain construction are enhanced by this methodology. Here, Edward Wakeland and colleagues compare various MASP-based strategies and discuss their advantages with reference to immunological traits.

Study on Retardation Mechanism of 3H, 99Tc, 137Cs, 237Np and 241AM in Compacted Sodium Bentonite

The apparent diffusion coefficients were measured at room temperature (about 23°C) under atmospheric condition by the one-dimensional non-steady state diffusion method for 3H, 99Tc, 137Cs, 237Np and 241Am in compacted sodium-bentonite saturated with water. Sodium-bentonite, which is commercially available as KunigelVl®, was used in this study. Experiments were carried out in the density range of 0.4–2.0 (×103kg/m3). Bentonite in the cell was prepared to be saturated with distilled water. The measured apparent diffusion coefficient decreases with increasing dry density of bentonite. That the apparent diffusion coefficient of 3H decreased as a function of dry density of bentonite appears to be the effect of the change of porous structure with dry density of bentonite. 99Tc may be retarded by anion-exclusion because dominant diffusion specie of 99Tc is pertechnetate ion under atmospheric condition. Retardation for 137Cs may be caused by ion-exchange on bentonite. The sorption, anion-exclusion and molecular filtration are considered as a retardation mechanism for 237Np and 241Am because those dominant species are negatively charged and of large ionic size.

The cascading, interrelated roles of interleukin-1, interleukin-2, and interleukin-6 in murine anti-CD3-driven T cell proliferation

T cell stimulation occurs following interaction of T cell receptor (TcR) with processed antigen presented by autologous accessory cells (AC). The effects of antigen stimulation on T cells are mimicked by monoclonal antibodies (Mabs) defining proteins of the TcR-CD3 complex. In this study, we examine the roles of T cell density, AC density, divalent and polyvalent forms of anti-CD3 Mab, and the cytokines interleukin (IL)-1, IL-2, and IL-6 in T cell activation and proliferation. Stringently AC-depleted T cells do not proliferate in response to Con A or divalent anti-CD3; however, polyvalent anti-CD3 provides a powerful signal for isolated resting T cell proliferation. Recombinant (r)IL-2 strongly amplifies T cell proliferation in response to anti-CD3, whereas rIL-1 exerts no direct effects on anti-CD3-stimulated T cells. In the presence of AC, however, rIL-1 augments T cell proliferation to anti-CD3. Recombinant IL-6 promotes T cell proliferation among T cells stimulated with polyvalent but not divalent anti-CD3. As deduced by Northern blot analysis, rIL-1 increases cytoplasmic levels of IL-6 mRNA in AC. Recombinant IL-6, in turn, amplifies the accumulation of stable IL-2 transcripts in purified T cells stimulated with polyvalent anti-CD3. Hence, IL-1, IL-6, and IL-2 support T cell proliferation through cascading effects at the level of gene transcription. The cytokines evaluated in this study, however, do not fully reconstitute AC functions in promoting anti-CD3 Mab T cell proliferation.

Analysis of fifty cases of facial palsy due to otitis media

Fifty cases of facial palsy (FP) due to otitis media treated in our hospital during the 10-year period from 1972 to 1981 were analyzed. The averaged percentage of this incidence was 3.1% of all the FP occurring. FP due to otitis media acuta (OMA) was frequently seen in infants. FP due to otitis media chronica (OMC) tended to occur in combination with cholesteatoma or acute exacerbations of infection. Paralyses were generally mild and bacteria from the otorrhea were similar to those of OMC without FP. When present, sites of dehiscence of the facial canal were most frequently seen in its horizontal portion. Electromyographically, the posterior (mastoid) side of the horizontal portion of the facial nerve bundle seemed to be related to the branch to the orbicularis oculi muscle, while the anterior (stapes) side was directed to the orbicularis oris muscle.