Triple-negative breast cancer on contrast-enhanced MRI and synthetic MRI: A comparison with non-triple-negative breast carcinoma.

PURPOSE: This study aimed to compare the characteristics of triple-negative breast cancer (TNBC) with non-TNBC on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and synthetic MRI. METHOD: This retrospective study included 79 patients with histopathologically proven breast cancer (TNBC: 16, non-TNBC: 63) who underwent synthetic MRI. Using synthetic MR images, we obtained T1 and T2 relaxation times in breast lesions before (Pre-T1, Pre-T2, Pre-PD) and after (Gd-T1, Gd-T2, Gd-PD) contrast agent injection. Subsequently, we calculated the ΔT1 (Pre-T1 - Gd-T1), ΔT2 (Pre-T2 - Gd-T2), Pre-T1/T2, and Gd-T1/T2. We compared the aforementioned quantitative values, as well as several morphologic features between TNBCs and non-TNBCs that were identified on DCE-MRI. RESULTS: The multivariate analyses revealed that the Pre-T2 (P = 0.037) and the presence of rim enhancement (P-RIM) (P = 0.034) were significant and independent predictors of TNBC. The area under the receiver operating characteristics curve for all breast cancers was greater when a combination of Pre-T2 and P-RIM (Pre-T2＋P-RIM; Method 3, AUC (area under the curve) = 0.858) was used to distinguish between TNBCs and non-TNBCs versus the use of either Pre-T2 alone (Method 1, AUC = 0.786) or P-RIM alone (Method 2, AUC = 0.747). CONCLUSIONS: Pre-T2 obtained using synthetic MRI and P-RIM identified on DCE-MRI allowed the differentiation between TNBCs and non-TNBCs. However, these results are preliminary and need to be verified by further studies.

Micro-CT of Pseudocneorhinus bifasciatus by projection X-ray microscopy.

The projection X-ray microscope utilises a very small X-ray source emitted from a thin (0.1-3 microm) target metal film excited by the focused electron beam of a scanning electron microscope. When an object is placed just below the target metal film, the diverging X-rays enlarge the shadow of the object. Because no X-ray optics such as a zone-plate is used, the focal depth is, in principle, infinitely large. We exploited this to apply projection X-ray microscopy to three-dimensional (3-D) structure analysis by means of cone-beam computed tomography. The projection images of a small arthropod (Pseudocneorhinus bifasciatus, 5 mm in length), was recorded at 3 degrees increments over the whole range (360 degrees) of a stepping-motor-controlled sample rotator. A 3-D image was reconstructed from corn-beam projections using a filtered back-projection algorithm. The reconstructed 3-D image showed in detail the internal structure of an opaque object.

Point mutation detection with the sandwich method employing hydrogel nanospheres by the surface plasmon resonance imaging technique.

We propose a surface modification procedure to construct DNA arrays for use in surface plasmon resonance (SPR) imaging studies for the highly sensitive detection of a K-ras point mutation, enhanced with hydrogel nanospheres. A homobifunctional alkane dithiol was adsorbed on Au film to obtain the thiol surface, and ethyleneglycol diglycidylether (EGDE) was reacted to insert the ethyleneglycol moiety, which can suppress nonspecific adsorption during SPR analysis. Then streptavidin (SA) was immobilized on EGDE using tosyl chloride activation. Biotinylated DNA ligands were bound to the SA surface via biotin-SA interaction to fabricate DNA arrays. In SPR analysis, the DNA analyte was exposed on the DNA array and hybridized with the immobilized DNA probes. Subsequently, the hydrogel nanospheres conjugated with DNA probes were bound to the DNA analytes in a sandwich configuration. The DNA-carrying nanospheres led to SPR signal enhancement and enabled us to discriminate a K-ras point mutation in the SPR difference image. The application of DNA-carrying hydrogel nanospheres for SPR imaging assays was a promising technique for high throughput and precise detection of point mutations.

Flow-stress-induced discrimination of a K-ras point mutation by sandwiched polymer microsphere-enhanced surface plasmon resonance.

The highly sensitive detection of a K-ras point mutation with the aid of DNA-carrying microspheres as a flow-stress receptor is proposed at the surface of a surface plasmon resonance (SPR) biosensor. Single-stranded DNAs were immobilized onto epoxy-group-derivatized gold surfaces and the hybridization of DNA targets was monitored. The subsequent interaction with DNA-carrying micospheres enhanced the SPR response. The increase of flow rate during the event of dissociation changed the amount of detachment of the DNA-carrying microspheres for the mismatched pair. In addition, the viscosity was changed by addition of glycerol to the buffer. The increase of shear stress from the flow resulted in detachment of DNA-carrying microspheres hybridized with the mismatched sequence and increased the ability to discriminate a point mutation. This is a new method which not only increases the lower detection limit of evanescent wave-based biosensors, but also the ability to discriminate a point mutation which is a critical factor for ultrasensitive DNA detection in flow devices.