Effective combination of 3 imaging modalities in differentiating between malignant and benign palatal lesions.

OBJECTIVE: The aim of this study was to evaluate whether computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT) can effectively differentiate between malignant and benign palatal lesions. STUDY DESIGN: In total, 59 patients with palatal lesions (32 malignant and 27 benign), who underwent CT, MRI, and/or PET/CT imaging examinations and had histopathological diagnoses, were divided into an analysis group (n = 46) and a validation group (n = 13). Bone changes adjacent to the lesion, MRI signal intensity, apparent diffusion coefficient (ADC), time to peak enhancement (Tpeak), and maximum standardized uptake values (SUVmax) were evaluated in the analysis group. Diagnostic performance was individually assessed for each parameter for differentiating between malignant and benign lesions. A diagnostic decision tree was constructed by using useful parameters and its accuracy tested in the validation group. RESULTS: The frequency distribution of bone change types and Tpeak differed significantly between malignant and benign lesions. The ADC of malignant lymphoma was significantly lower than that of other lesions. The other parameters did not distinguish between lesion types. The accuracy of the decision tree, constructed by using bone change types, ADC, and Tpeak, was 87.5%. CONCLUSIONS: Bone change types, ADC values, and Tpeak are useful for differentiating between malignant and benign palatal lesions.

Differences in the Clinical Characteristics of Persistent Idiopathic Facial Pain (Atypical Odontalgia) Patients with or Without Neurovascular Compression of the Trigeminal Nerve.

BACKGROUND: Persistent idiopathic facial pain (PIFP) is the unexplained pain along the territory of the trigeminal nerve, including nonorganic tooth pain called atypical odontalgia (AO). Though PIFP is debilitating to patients' livelihood and well-being, its pathophysiology remains poorly understood. Although neurovascular compression (NVC) of the trigeminal nerve is known to be associated with trigeminal neuralgia (TN), the relationship between NVC and other orofacial pains has not been fully elucidated. METHODS: In this study, we investigated the differences in the characteristics of PIFP (primarily AO) patients in the presence or absence of NVC. A retrospective analysis was performed on data from 121 consecutive patients who had been diagnosed with unilateral PIFP according to the criteria of the International Classification of Headache Disorders (ICHD)-3 and underwent magnetic resonance imaging scans of the head. RESULTS: In the group without NVC, characteristic findings were significant for psychiatric morbidity, somatization, and pain disability, when compared with the group with NVC. Furthermore, the group without NVC exhibited significant headache, noncardiac chest pain, shortness of breath, and pain catastrophizing. CONCLUSIONS: These results suggest that PIFP patients can be divided into two groups: one consistent with a neuropathic pain phenotype when NVC is present and a functional somatic symptom phenotype when presenting without NVC. Our findings may enable a more precise understanding of pathophysiology of PIFP and lead to better treatment strategies.

Oral carcinoma: Clinical evaluation using diffusion kurtosis imaging and its correlation with histopathologic findings.

PURPOSE: In this study, we aimed to determine the usefulness of diffusion kurtosis imaging (DKI) as a noninvasive method for evaluation of the histologic grade and lymph node metastasis in patients with oral carcinoma. MATERIALS AND METHODS: Twenty-seven patients with oral carcinoma were examined with a 3-T MR system and 16-channel coil. DKI data were obtained by a single-shot echo-planar imaging sequence with repetition time, 10,000 ms; echo time, 94 ms; field of view, 250 × 204.25 ms; matrix, 120 × 98; section thickness, 4 mm; four b values of 0, 500, 1000, and 2000 s/mm2; and motion-probing gradients in three orthogonal directions. Diffusivity (D) and kurtosis (K) were calculated using the equation: S = S0 ∙ exp(-b ∙ D + b2 ∙ D2 ∙ K/6). Conventional apparent diffusion coefficient (ADC) was also calculated. The MR images were compared with the histopathologic findings. RESULTS: Relative to the histologic grades (Grades 1, 2, and 3) of the 27 oral carcinomas, D values showed a significant inverse correlation (r = -0.885; P < 0.001) and K values showed a significant positive correlation (r = 0.869; P < 0.001), whereas ADC values showed no significant correlation (r = -0.311; P = 0.115). When comparing between metastatic and non-metastatic lymph nodes, significant differences in the D values (P < 0.001) and K values (P < 0.001), but not the ADC values (P = 0.110) became apparent. CONCLUSIONS: In patients with oral carcinoma, DKI seems to be clinically useful for the evaluation of histologic grades and lymph node metastasis.

Colorectal carcinoma: Ex vivo evaluation using q-space imaging; Correlation with histopathologic findings.

BACKGROUND: Although the prognosis of colorectal carcinoma (CRC) patients depends on the histologic grade (HG) and lymph node metastasis (LNM), accurate preoperative assessment of these prognostic factors is often difficult. PURPOSE: To assess the HG and extent of LNM by q-space imaging (QSI) for preoperative diagnosis of CRC. STUDY TYPE: Prospective. SPECIMEN: A total of 20 colorectal tissue samples containing adenocarcinomas and resected lymph nodes (LNs). FIELD STRENGTH/SEQUENCE: QSI was performed with a 3T MRI system using a diffusion-weighted echo-planar imaging sequence: repetition time, 10,000 msec; echo time, 216 or 210 msec; field of view, 113 × 73.45 mm; matrix, 120 × 78; section thickness, 4 mm; and 11 b values ranging from 0 to 9000 s/mm2 . ASSESSMENT: The mean displacement (MDP; µm), zero-displacement probability (ZDP; arbitrary unit [a.u.]), kurtosis (K; a.u.), and apparent diffusion coefficient (ADC) were analyzed by two observers and compared with histopathologic findings. STATISTICAL TESTS: Spearman's rank correlation coefficient, Mann-Whitney U-test, and ROC curve analyses. RESULTS: For all 20 carcinomas, the MDP, ZDP, K, and ADC were 8.87 ± 0.37 µm, 82.0 ± 6.2 a.u., 74.3 ± 3.0 a.u., and 0.219 ± 0.040 × 10-3 mm2 /s, respectively. The MDP (r = -0.768; P < 0.001), ZDP (r = 0.768; P < 0.001), and K (r = 0.785; P < 0.001) were significantly correlated with the HG of CRC, but not the ADC (r = 0.088; P = 0.712). There were also significant differences in the MDP, ZDP, and K between metastatic and nonmetastatic LNs (all, P < 0.001), but not the ADC (P = 0.082). In the HG of CRC and LNM, the area under the curve was significantly greater for MDP, ZDP, and K than for ADC. DATA CONCLUSION: QSI provides useful diagnostic information to assess the HG and extent of LNM in CRC. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1059-1068.

Colorectal carcinoma: Ex vivo evaluation using 3-T high-spatial-resolution quantitative T2 mapping and its correlation with histopathologic findings.

PURPOSE: In this study, we aimed to evaluate the feasibility of determining the mural invasion depths of colorectal carcinomas using high-spatial-resolution (HSR) quantitative T2 mapping on a 3-T magnetic resonance (MR) scanner. MATERIALS AND METHODS: Twenty colorectal specimens containing adenocarcinomas were imaged on a 3-T MR system equipped with a 4-channel phased-array surface coil. HSR quantitative T2 maps were acquired using a spin-echo sequence with a repetition time/echo time of 7650/22.6-361.6ms (16 echoes), 87×43.5-mm field of view, 2-mm section thickness, 448×224 matrix, and average of 1. HSR fast-spin-echo T2-weighted images were also acquired. Differences between the T2 values (ms) of the tumor tissue, colorectal wall layers, and fibrosis were measured, and the MR images and histopathologic findings were compared. RESULTS: In all specimens (20/20, 100%), the HSR quantitative T2 maps clearly depicted an 8-layer normal colorectal wall in which the T2 values of each layer differed from those of the adjacent layer(s) (P<0.001). Using this technique, fibrosis (73.6±9.4ms) and tumor tissue (104.2±6.4ms) could also be clearly differentiated (P<0.001). In 19 samples (95%), the HSR quantitative T2 maps and histopathologic data yielded the same findings regarding the tumor invasion depth. CONCLUSIONS: Our results indicate that 3-T HSR quantitative T2 mapping is useful for distinguishing colorectal wall layers and differentiating tumor and fibrotic tissues. Accordingly, this technique could be used to determine mural invasion by colorectal carcinomas with a high level of accuracy.

Trigeminal neuralgia: differences in magnetic resonance imaging characteristics of neurovascular compression between symptomatic and asymptomatic nerves.

OBJECTIVES: Neurovascular compression (NVC) of the trigeminal nerve is the primary cause of trigeminal neuralgia (TN) but is known to occur in both symptomatic and asymptomatic nerves. The purposes of this study were to evaluate the relationship between the magnetic resonance imaging (MRI) findings regarding the site of NVC and the manifestation of TN symptoms. METHODS: In 147 patients with unilateral TN, the presence or absence of NVC was evaluated on MRI in both symptomatic and asymptomatic nerves. In cases with NVC, the shortest distance from the trigeminal nerve root to the responsible vessel was measured. RESULTS: The mean distance from the trigeminal nerve root to the site of NVC in asymptomatic nerves (3.85 ± 2.69 mm) was significantly greater than that in symptomatic nerves (0.94 ± 1.27 mm). When the distance was 3 mm or less, the rate of the manifestation of TN symptoms was 83.1% (103/124). On the other hand, it was only 19.6% (9/46) in cases with a distance of greater than 3 mm. CONCLUSIONS: Whether or not NVC of the trigeminal nerve was symptomatic was closely related to the distance from the trigeminal nerve root to the responsible blood vessel.

Effect of enamel surface modification by novel aqueous phosphate-type fluoride surfactants.

Three novel aqueous fluoride surfactants (F4, F6, and F8) and a positive control (10F2S-3I) were applied to bovine enamel and the surface free energy was calculated by measuring the surface contact angles of three liquids: distilled water, α-bromonaphthalene and diiodomethane. The specimens were stored in water for 90 days, and then immersed in acetic acid/sodium acetate. The modified specimens recorded higher contact angles and lower surface free energy immediately after treatment than the control (p<0.05). Less calcium dissolved from the modified enamel surfaces than the control, with the F8-modified specimen registering significantly lower values than those of the F4, F6 and 10F2S-3I groups (p<0.05). These results suggest that the novel aqueous phosphate-type fluoride surfactant F8 is the most effective anti-cariogenic surface modifier.

Synthesis and antimicrobial activity of quaternary ammonium silane coupling agents.

Fourteen novel silane coupling agents with a quaternary ammonium group introduced into the molecule, [CH(2)=CHCH(2)N(+)(CH(3))(C(n)H(2n+1))(CH(2))(3)Si(OCH(3))(3)]X(-) (n-X, n=10-18, X=Cl, Br, or I), were synthesized with the aim of using these agents to make material surfaces antimicrobial for a long period of time. Measurements of the minimum inhibitory concentrations (MIC) against 12 kinds of fungi and bacteria revealed that the coupling agent with a C(10) alkyl chain and Cl- or Br- counter-ion (10-Cl or 10-Br) has the highest antimicrobial activity among the n-X agents synthesized, but 14-Cl and 14-Br showed the highest activity on a modified porcelain plate.

Gold-colored organic crystals formed from an azobenzene derivative.

The azobenzene derivative 4,4'-bis{1-[2-(N,N-dimethylamino)]ethoxy}azobenzene has been found to form gold-colored plate-like crystals. The thin film obtained by accumulating the crystals has a maximum specular reflectance of ca. 15% for visible light. To investigate the structure of the gold-colored crystals, UV-vis, X-ray diffraction (XRD), and IR analyses were performed. UV-vis measurements show that the molecules in the crystal produce J-aggregates. Furthermore, XRD measurements estimated the long-range d-spacing for the crystal as 1.51 nm. These results indicate that the azobenzene moieties are oriented diagonally against the crystal surfaces. When the crystals are placed in a desiccator (humidity 40%) for 1 d, their color changes from gold to yellow. IR measurements show that the gold-colored crystals contain crystallized water, while there are no water molecules in the yellow crystals, in which the structure of the J-aggregates is disrupted. These results show that the crystallized water molecules are essential for the formation of the J-aggregates and the resultant gold luster.

Evaluation of gastric cancer by high-resolution three-dimensional CISS MR imaging in vitro.

OBJECTIVE: The objective of this study was to demonstrate the usefulness of high-resolution three-dimensional (3D) constructive interference in steady-state (CISS) MR imaging for evaluating mural invasion and the morphologic features of gastric cancers in vitro. MATERIALS AND METHODS: High-resolution 3D-CISS MR images were obtained in three surgical specimens containing three different gastric cancers. RESULTS: In early carcinoma, advanced carcinoma, and leiomyosarcoma, the depth of mural invasion at 3D-CISS MR imaging correlated well with the histopathologic stage. CONCLUSION: High-resolution 3D-CISS MR imaging is a useful method for evaluating mural invasion and the macroscopic features of gastric cancers in vitro.

Tissue characterization of head and neck lesions using diffusion-weighted MR imaging with SPLICE.

PURPOSE: The purpose of this study was to evaluate the usefulness of diffusion-weighted (DW) MR imaging with split acquisition of fast spin-echo signals (SPLICE) in the tissue characterization of head and neck mass lesions. PATIENTS AND METHODS: DW MR images of 67 head and neck mass lesions were obtained using SPLICE with b-factors of 0 and 771s/mm(2). The lesions were classified into three categories: 16 cysts, 32 benign tumors, and 19 malignant tumors. After ADC maps were constructed for all lesions, ADC values were calculated and compared among the three categories. RESULTS: No case showed severe image distortion on DW MR imaging with SPLICE, and reliable ADC maps and ADC values were obtained in all cases. The mean ADC value of cysts was 2.41+/-0.48 x 10(-3)mm(2)/s, which was significantly higher than that of benign (1.48+/-0.62 x 10(-3)mm(2)/s) and malignant (1.23+/-0.45 x 10(-3)mm(2)/s) tumors (P<0.001). However, there was no significant difference between the ADC values of benign and malignant tumors (P=0.246). When an ADC value of 2.10 x 10(-3)mm(2)/s or higher was used as the diagnostic criterion for cysts, the sensitivity, specificity, and accuracy were 94%, 88%, and 90%, respectively. CONCLUSION: SPLICE was considered a recommended DW MR imaging technique for the head and neck. Although ADC values were useful in differentiating cysts from tumors, they contributed little in predicting malignancy.

Colorectal Carcinoma: Local Tumor Staging and Assessment of Lymph Node Metastasis by High-Resolution MR Imaging in Surgical Specimens.

Purpose. To assess the accuracy of high-resolution MR imaging as a means of evaluating mural invasion and lymph node metastasis by colorectal carcinoma in surgical specimens. Materials and Methods. High-resolution T1-weighted and T2-weighted MR images were obtained in 92 surgical specimens containing 96 colorectal carcinomas. Results. T2-weighted MR images clearly depicted the normal colorectal wall as consisting of seven layers. In 90 (94%) of the 96 carcinomas the depth of mural invasion depicted by MR imaging correlated well with the histopathologic stage. Nodal signal intensity on T2-weighted images (93%) and nodal border contour (93%) were more accurate than nodal size (89%) as indicators of lymph node metastasis, and MR imaging provided the highest accuracy (94%-96%) when they were combined. Conclusion. High-resolution MR imaging is a very accurate method for evaluating both mural invasion and lymph node metastasis by colorectal carcinoma in surgical specimens.

Synthesis of bone formation deriving biosilanes.

Six silane coupling agents having amide group (biosilanes) were synthesized with the aim to construct the material surface that allows cells to be compatible with it without their destruction. These agents were expected to make a soft landing to cytoplasm through the hydrogen bonding between their amide groups and cells. Evaluations of cell affinity using glass substrates modified with the synthesized biosilanes revealed that many cells remain on the modified glass plate. In addition, the implantation into the body of immunodeficient mouse of a composite material composed of porous hydroxyapatite and osteoblast showed the formation of a bone-like structure.

Synthesis and antibacterial activity of quaternary ammonium salt-type antibacterial agents with a phosphate group.

Quaternary ammonium salts are frequently used as antibacterial agent that disrupts cell membrane through the binding of their ammonium cations to anionic sites in the outer layer tissue of bacteria. This article describes the synthesis of quaternary ammonium salt-type antibacterial agents with a phosphate group that strongly binds to hydroxyapatite and bromide ion as counterion. Evaluation of the antibacterial activity of the synthesized compounds in terms of minimum inhibitory concentration (MIC test) showed that the compounds exhibit an excellent antibacterial activity on a variety of bacteria including Gram-positive and Gram-negative bacteria, yeast, and fungi.

Colorectal carcinoma: in vitro evaluation with high-spatial-resolution 3D constructive interference in steady-state MR imaging.

PURPOSE: To retrospectively assess the accuracy of high-spatial-resolution three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance (MR) imaging in the evaluation of mural invasion of colorectal carcinoma by using prospectively obtained in vitro images, with histopathologic analysis as the reference standard. MATERIALS AND METHODS: Institutional review board approval was obtained for the prospective and retrospective components of this study, with informed consent for the former and waiver of informed consent for the latter. Surgical specimens were obtained in 92 patients (61 men, 31 women; mean age, 65 years) and contained 96 colorectal carcinomas. Specimens were examined with a 1.5-T MR system and a 4-cm-diameter loop coil. High-spatial-resolution 3D CISS MR images were obtained with 80 x 80-mm field of view, 512 x 512 matrix, and 0.7-mm section thickness, which resulted in a 0.017-mm(3) voxel size. The 3D data sets were postprocessed with surface-rendering software to generate virtual MR endoscopic images. The 3D CISS MR images were compared with histopathologic findings, and virtual MR endoscopic images were compared with macroscopic findings at surgery. Statistical analysis was performed with Spearman rank correlation. RESULTS: In 92 (96%) colorectal carcinomas, the depth of mural invasion depicted by 3D CISS MR imaging correlated well with the histopathologic stage, although the stage assigned with 3D CISS MR imaging was higher than that assigned with histopathologic analysis in four (4%) carcinomas (r = 0.976, P < .001). Sensitivity, specificity, and accuracy were 100%, 94%-96%, and 98%-100%, respectively. In 91 (95%) carcinomas, virtual MR endoscopy clearly depicted the macroscopic type of carcinoma, including gross configuration and tumor ulceration (r = 0.916, P < .001). CONCLUSION: High-spatial-resolution 3D CISS MR imaging has high diagnostic accuracy in the in vitro evaluation of mural invasion and macroscopic features of colorectal carcinomas.

Three-body-wear resistance of the experimental composites containing filler treated with hydrophobic silane coupling agents.

This paper evaluated the wear resistance of resin composite materials with fillers which were modified with a novel hydrophobic silane coupling agent. The novel silane coupling agent containing hydrophobic phenyl group 3-(3-methoxy-4-methacryloyloxyphenyl)propyltrimethoxysilane (p-MBS) was synthesized. The experimental light-cure hybrid composites containing 85wt% of filler modified with this silane were formulated. Twelve specimens were prepared for the three-body-wear test with the ACTA machine and the collected data were analyzed statistically using a one-way ANOVA and Tukey's multiple comparison test as the post hoc test. The wear of the composites containing fillers treated with p-MBS was significantly lower compared with the composite materials containing fillers pretreated with 3-methacryloyloxypropyltrimethoxysilane or the commercially composites (AP-X and ELS extra low shrinkage) after a wear test for 200,000 cycles (p<0.05). It is suggested that the resin composites containing fillers modified with the novel hydrophobic silane has high wear resistant, because of the coupling layers treated with this silane had an excellent affinity with the base resin and formed a highly hydrophobic layer on the filler surface.

Formation of wormlike aggregates of fluorocarbon-hydrocarbon hybrid surfactant by Langmuir-Blodgett transfer and alignment of gold nanoparticles.

A novel anionic fluorocarbon-hydrocarbon hybrid surfactant (SS-Hyb-Na+) with a disulfide group has been synthesized from 11-bromo-1-undecanal and perfluorohexylethyl iodide via three steps. The Langmuir-Blodgett (LB) transfer of the 1:100 (mol/mol) mixed monolayer of SS-Hyb-Na+ and stearyl alcohol (C18OH) formed on an aqueous solution containing a cationic polymer, poly(diallyldimethylammonium chloride) (PDDA+Cl-) onto a hydrophobic silicon wafer yields the formation of wormlike aggregates consisting of SS-Hyb-/PDDA+ polyion complexes. It is found that the aggregates align along the withdrawal direction of the wafer substrate. When the wafer on which the wormlike aggregates exist is immersed into the dispersion of gold nanoparticles (Au NPs) prepared by the citrate reduction method, Au NPs align along the wormlike structures. Even though the surface of the wafer is placed either vertical or parallel to the monolayer compression direction during the LB transfer, the one-dimensional (1D) array of Au NPs is observed along the withdrawal direction of the wafer. This indicates that the wormlike aggregates of SS-Hyb-/PDDA+ complexes are aligned during the LB transfer, and the aligned aggregates behave as a scaffold in the 1D array of Au NPs.

Preparation of thin polymer films with controlled drug release.

Poly(N-isopropylacrylamide) (PAAm) is a thermal responsive polymer that undergoes a structural change in aqueous solution at its lower critical solution temperature (LCST). PAAm-modified silicon substrates were prepared and the effect of PAAm density on the thermal response of the modified surface was examined in terms of changes in the water contact angle as a basis for applying the structural change of the polymer to controlled drug release. Changes with temperature in the ability to load and release of the modified layer for drug were also examined using 2-acetoxybenzoic acid (aspirin) as a model drug. The amount of PAAm was found to greatly affect the thermal response and the ability to load and release of the modified layer for aspirin.

Preparation of thin polymer films with drug release and protein adsorption resistance.

Thin polymer films with the ability of both drug release and protein adsorption resistance were formed on silicon substrates and silica particles. The films were made of a block copolymer of poly(N-isopropylacrylamide) (p(AAm)) that can load and release drugs and poly(2-methoxyethyl methacrylate) (p(MEMA)) that can suppress protein adsorption. Aspirin and bovine serum albumin were respectively used as model substances for testing the abilities of the films to load and release drugs and to suppress protein adsorption. The films were immersed in a phosphate buffer saline (pH 7.4) for 100 days to evaluate their water resistance. The experimental results showed that the films have both drug release and protein adsorption resistance and are highly stable against PBS.