Wing P. Chan

Differentiation of soft tissue benign and malignant peripheral nerve sheath tumors with magnetic resonance imaging

PURPOSE The objective of this study was to differentiate the magnetic resonance (MR) imaging appearance of benign peripheral nerve sheath tumors (PNSTs) from that of malignant PNSTs. MATERIALS AND METHODS Twenty-six patients who underwent MR imaging and had a histologic diagnosis of benign (schwannoma, n=16; neurofibroma, n=1) or malignant (n=9) PNST were retrospectively reviewed. The size, location, shape, margin, and signal intensities of the tumors on precontrast and gadolinium-enhanced MR imaging were analyzed. In each patient, the presence or absence of split fat, target, and fascicular signs was determined. RESULTS The mean size of the benign PNSTs (3.4 cm, S.D.=2.5 cm) was significantly smaller than that of the malignant tumors (8.2 cm, S.D.=3.1 cm) (P<.001). Seventeen (65.4%) of the 26 tumors were spindle shaped or ovoid (12 benign and 5 malignant tumors). Contiguity with specific nerves was identified in 15 (88.2%) of the 17 benign PNSTs but in none of the malignant tumors (P<.05). Well-defined margins were noted in all 17 benign PNSTs but in only 3 (33.3%) of the 9 malignant tumors (P<.001). Five (55.6%) of the 9 malignant PNSTs but none of the benign tumors showed signal intensity change in adjacent soft tissue (P<.05). There was no significant difference in signal intensity between the benign and malignant tumors on T(1)-weighted, T(2)-weighted, and contrast-enhanced MR images. The split fat and target signs were present more frequently in the benign PNSTs than in the malignant PNSTs (P<.05). CONCLUSIONS Benign and malignant PNSTs are often spindle shaped. Recognition of contiguity with adjacent nerves, a well-defined margin, and the presence of the split fat sign may suggest benignity. Imaging features suggestive of malignancy can be a larger size and an infiltrative margin.

Fibrin glue mixed with platelet-rich fibrin as a scaffold seeded with dental bud cells for tooth regeneration

Odontogenesis is a complex process with a series of epithelial‐mesenchymal interactions and odontogenic molecular cascades. In tissue engineering of teeth from stem cells, platelet‐rich fibrin (PRF), which is rich in growth factors and cytokines, may improve regeneration. Accordingly, PRF was added into fibrin glue to enrich the microenvironment with growth factors. Unerupted second molar tooth buds were harvested from miniature swine and cultured in vitro for 3 weeks to obtain dental bud cells (DBCs). Whole blood was collected for the preparation of PRF and fibrin glue before surgery. DBCs were suspended in fibrin glue and then enclosed with PRF, and the DBC‐fibrin glue‐PRF composite was autografted back into the original alveolar sockets. Radiographic and histological examinations were used to identify the regenerated tooth structure 36 weeks after implantation. Immunohistochemical staining was used to detect proteins specific to tooth regeneration. One pig developed a complete tooth with crown, root, pulp, enamel, dentin, odontoblast, cementum, blood vessels, and periodontal ligaments in indiscriminate shape. Another animal had an unerupted tooth that expressed cytokeratin 14, dentin matrix protein‐1, vascular endothelial growth factor, and osteopontin. This study demonstrated, using autogenic cell transplantation in a porcine model, that DBCs seeded into fibrin glue‐PRF could regenerate a complete tooth. Copyright

Runx2-mediated bcl-2 gene expression contributes to nitric oxide protection against hydrogen peroxide-induced osteoblast apoptosis

Nitric oxide (NO) can regulate osteoblast activities. This study was aimed to evaluate the protective effects of pretreatment with sodium nitroprusside (SNP) as a source of NO on hydrogen peroxide‐induced osteoblast insults and its possible mechanisms. Exposure of human osteosarcoma MG63 cells to hydrogen peroxide significantly increased cellular oxidative stress, but decreased ALP activity and cell viability, inducing cell apoptosis. Pretreatment with 0.3 mM SNP significantly lowered hydrogen peroxide‐induced cell insults. Treatment of human MG63 cells with hydrogen peroxide inhibited Bcl‐2 mRNA and protein production, but pretreatment with 0.3 mM SNP significantly ameliorated such inhibition. Sequentially, hydrogen peroxide decreased the mitochondrial membrane potential, but increased the levels of cytochrome c and caspase‐3 activity. Pretreatment with 0.3 mM SNP significantly lowered such alterations. Exposure to hydrogen peroxide decreased Runx2 mRNA and protein syntheses. However, pretreatment with 0.3 mM SNP significantly lowered the suppressive effects. Runx2 knockdown using RNA interference inhibited Bcl‐2 mRNA production in human MG63 cells. Protection of pretreatment with 0.3 mM SNP against hydrogen peroxide‐induced alterations in ALP activity, caspase‐3 activity, apoptotic cells, and cell viability were also alleviated after administration of Runx2 small interference RNA. Thus, this study shows that pretreatment with 0.3 mM SNP can protect human MG63 cells from hydrogen peroxide‐induced apoptotic insults possibly via Runx2‐involved regulation of bcl‐2 gene expression. J. Cell. Biochem. 108: 1084–1093, 2009.

Intervertebral Disk Degeneration Related to Reduced Vertebral Marrow Perfusion at Dynamic Contrast-Enhanced MRI

OBJECTIVE The purpose of this study was to use dynamic contrast-enhanced MRI to ascertain the relation between intervertebral disk degeneration and lumbar vertebral marrow blood perfusion. SUBJECTS AND METHODS We recruited 25 patients (50 vertebral bodies) who underwent dynamic contrast-enhanced MRI of the lumbar spine. The peak signal enhancement of each vertebral body was calculated from the time signal after curve fitting of a pharmacokinetic model. We controlled for other variables that might have affected blood perfusion by assessing two vertebral bodies in each patient. The 25 patients were divided into three groups. In group 1, one of the vertebral bodies (L1 or L3) evaluated was between two adjacent normal disks and the other was between two adjacent degenerated disks. In group 2, each of the two vertebral bodies evaluated was between two normal disks. In group 3 each of the two vertebral bodies evaluated was between two degenerated disks. RESULTS Without normalization by minimization of other variables, there were no statistically significant differences in original peak enhancement values among groups 1, 2, and 3 (p = 0.179). After normalization, the peak enhancement in group 1 (0.846 +/- 0.060) was significantly lower than that in group 2 (0.988 +/- 0.047) (p = 0.003) or group 3 (0.973 +/- 0.081) (p = 0.008). CONCLUSION After normalization, lumbar vertebral marrow perfusion correlated well with intervertebral disk degeneration evaluated with dynamic contrast-enhanced MRI. Blood perfusion was 14% less in the vertebral body marrow between two degenerated disks than in vertebral marrow between two normal disks.

Malignant transformation of an ovarian mature cystic teratoma: Computed tomography findings

IntroductionThe malignant transformation of an ovarian mature cystic teratoma is rare. We presented such a case of a 46-year-old woman with characteristic computed tomography (CT) findings.Case report The patient had suffered from fullness and tenderness of the lower abdomen for one year. A high serum CA-125 level was noted. Computed tomography images showed a left adnexal mass with fat, calcification and soft tissue components, and areas of invasion through the teratoma wall.OutcomeThe histologic diagnosis was compatible with a squamous cell carcinoma arising from a mature cystic teratoma of the ovary.

Inflammatory pseudotumor of the spleen: CT and MRI findings.

We report the CT and MRI findings of an inflammatory pseudotumour of the spleen, which is an extremely rare benign inflammatory lesion. CT scans obtained 1 h after contrast administration and T2-weighted MRI images clearly demonstrated the central fibrosis and peripheral granuloma of this lesion.Inflammatory pseudotumors rarely occur in the spleen. We report such a case with characteristic computed tomography (CT) and magnetic resonance imaging (MRI) findings. A CT scan showed an isodense nodular mass with gradual mild enhancement on delayed-phase contrast-enhanced images. MRI showed a mass with isointense signal on T1-weighted images and hypointense signal on T2-weighted images. The tumor mass showed progressive inhomogeneous enhancement on gadolinium-enhanced images. The patient received splenectomy, and histologic diagnosis was compatible with inflammatory pseudotumor.

Relationship of Idiopathic Osteonecrosis of the Femoral Head to Perfusion Changes in the Proximal Femur by Dynamic Contrast-Enhanced MRI

OBJECTIVE The purpose of this article is to relate intramedullary perfusion of the proximal femur to severity of osteonecrosis of the femoral head by using dynamic contrast-enhanced MRI (DCE-MRI). SUBJECTS AND METHODS Twelve patients (14 symptomatic hips) who underwent DCE-MRI and had subsequent core decompression of the femoral head were examined. Hips were graded for severity according to MRI findings and were assigned scores of 0 (negative findings), 1 (focal marrow abnormalities), and 2 (subchondral collapse). Thirteen asymptomatic hips acted as controls. The DCE-MRI data were analyzed by use of a pharmacokinetic two-compartment model. RESULTS Compared with control hips, there was significantly greater peak enhancement in the femoral head in hips of all grades (p < 0.001) and in the femoral neck (p = 0.001) and intertrochanteric area (p = 0.001) in grade 2 hips. The time to peak was significantly delayed in the femoral head in grade 0 hips (p = 0.02) and in the intertrochanteric area in grade 2 hips (p = 0.003) compared with the controls. CONCLUSION As evaluated by DCE-MRI, intramedullary peak enhancement in the femoral head increased with progression of idiopathic osteonecrosis of the femoral head, whereas there was delayed peak enhancement in the femoral head in hips with negative findings and intertrochanteric stasis in advanced osteonecrosis of the femoral head. Such perfusion changes as shown on MRI can occur with early osteonecrosis in the absence of other MRI abnormalities.

Prominent Vessel Sign on Susceptibility-Weighted Imaging in Acute Stroke: Prediction of Infarct Growth and Clinical Outcome

Background and Purpose Predicting the risk of further infarct growth in stroke patients is critical to therapeutic decision making. We aimed to predict early infarct growth and clinical outcome from prominent vessel sign (PVS) identified on the first susceptibility-weighted image (SWI) after acute stroke. Materials and Methods Twenty-two patients with middle cerebral artery (MCA) infarction had diffusion-weighted imaging, SWI, MR angiography, and clinical evaluation using the National Institutes of Health Stroke Scale at 7–60 hours and 5–14 days after stroke onset. Late-stage clinical evaluation at 1 and 3 months used the modified Rankin Scale. The infarct area and growth were scored from 10 (none) to 0 (infarct or growth in all 10 zones) using the Alberta Stroke Program Early CT Score (ASPECTS) system. Results Infarct growth on the second MRI occurred in 13 of 15 patients with PVS on the first MRI and not in any patient without PVS (n=7; r=0.86, P<0.001). The extent of PVS was significantly correlated with infarct growth (r=0.82, P<0.001) and early-stage outcome (P=0.02). No between-group difference in late-stage clinical outcome was found. Conclusion PVS on the first SWI after acute MCA territory stroke is a useful predictor of early infarct growth. Extensive PVS within the large MCA territory is related to poor early-stage outcome and could be useful for clinical assessment of stroke.

Enhancement of Transdermal Delivery of Indomethacin and Tamoxifen by Far-Infrared Ray-Emitting Ceramic Material (BIOCERAMIC): A Pilot Study

BIOCERAMIC have been found to modulate various biological effects. Our earlier published research on various cell lines demonstrated that BIOCERAMIC promoted microcirculation, upregulated calcium-dependent nitric oxide and calmodulin, and exerted an antioxidant effect by increasing hydrogen peroxide scavenging ability. The development of pain relief systems requires most possible minimum doses and methods for effective local control of pain, so as to protect liver and renal function. There is also clinical necessary to develop targeted delivery of estrogen inhibitor in the breast using a local drug release system, to protect the breast from the increased cancer risk associated with the use of estrogen therapy. We compared the viscosity of BIOCERAMIC irradiated water and control water, and found that BIOCERAMIC might weaken the hydrogen bonds. Such breaks are caused by the loss of hydrogen bond covalence resulting from electron rearrangement. The purposes of this study were thus to investigated a transdermal drug delivery model using Franz cell apparatus for Indomethacin and Tamoxifen. The results showed that BIOCERAMIC enhanced the diffusion and permeability of the drugs. Therefore, we suggest that BIOCERAMIC might enhance the penetration performed by hydrogen bond weakening due to physical induction, and may facilitate local drug delivery in transdermal systems.

Proton magnetic resonance spectroscopy-guided biopsy for cerebral glial tumors.

BACKGROUND AND PURPOSE Although application of proton magnetic resonance (MR) spectroscopy in the diagnosis of brain tumors has been reported, the role of this technique as guidance for targeting biopsy of brain tumors is not well established. The usefulness and limitations of predicting tumor proliferative activity and pathological grading of brain gliomas based on samples obtained from proton MR spectroscopy-guided stereotactic biopsy also remains unclear. The purpose of this study was to evaluate the usefulness of single-voxel MR spectroscopy-guided stereotactic biopsy for cerebral gliomas and to correlate the findings of MR spectroscopy with proliferative activity (measured by Ki-67 labeling index) of tumors and pathological diagnosis. METHODS Localized proton spectra were obtained before stereotactic/surgical biopsy in 7 patients with glioma (8 lesions). Metabolic values in the spectra were measured semiquantitatively and correlated with the Ki-67 labeling index and pathological grade of each surgical specimen. RESULTS MR spectroscopy-guided biopsy was effective in obtaining a representative specimen for accurate pathological diagnosis in all patients, including 1 patient with multifocal glioma and 2 with diffusely infiltrated gliomas (gliomatosis cerebri). Those lesions with higher choline complex/creatine ratio (Cho/Cr) and lower N-acetyl-L-aspartate/creatine values in MR spectroscopy were higher grade tumors. Higher Ki-67 labeling index (indicating higher proliferative activity of tumor) with higher Cho/Cr ratios in MR spectroscopy were significantly correlated with tumor grade. CONCLUSIONS MR spectroscopy-guided biopsy was effective in obtaining a representative specimen for accurate pathological diagnosis, and the Cho/Cr ratio of MR spectra and Ki-67 labeling index were reliable predictors of glioma grade.