Adenovirus mediated gene transfer of tyrosinase gene on HepG2 cell by magnetic resonance imaging / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the transfect results of recombinant adenovirus vector carrying tyrosinase gene (Ad-tyr) in vitro by magnetic resonance imaging (MRI) after the Ad-tyr was transfected into HepG2 cell.</p><p><b>METHODS</b>The Ad-tyr which carried the full-length cDNA of tyrosinase gene was transfected into HepG2 cell. The transfected cells were scan by MRI sequences of T1 weighted image (T1WI) , T2 weighted image (T2WI) , and short time inversion recovery (STIR) to observe the MRI signals of expressed melanin. Masson-Fontana staining was performed to search for melanin granules in transfected cells. Real-time PCR method was used to search for cDNA of tyrosinase gene.</p><p><b>RESULTS</b>Ad-tyr was transfected into HepG2 cells and synthesized a large amount of melanin inside. The synthesized melanin of 1 x 10(6) cells which had been transfected by Ad-tyr with the 50, 150, and 300 multiplicity of infection separately were all sufficient to be detected by MRI and showed high signals in MRI T1WI, T2WI, and STIR sequences. The signal intensities of MRI were positively correlated to the amounts of transfected Ad-tyr. The melanin granules were found in HepG2 cells in Masson-Fontana staining. The cDNA amount of tyrosinase gene in transfected HepG2 cells, which was detected by real-time PCR, was remarkably higher than that in nontransfected cells.</p><p><b>CONCLUSION</b>The synthesized melanin of HepG2 cells, which controlled by expression of exogenous gene, can be detected by MRI, indicating that the adenovirus vector can efficiently carry the tyrosinase gene into HepG2 cells.</p>

Clinical significance of diffusion-weighted MRI with STIR-EPI in differential diagnosis of cervical lymph nodes / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility and efficacy of a new MRI imaging method--diffusion weighted imaging (DWI) with short TI version recovery-echo planar imaging (STIR-EPI) sequence in differentiating benign cervical lymph nodes from malignant ones. METHODS Twenty nasopharyngeal carcinoma patients and fourteen volunteers received both conventional MRI and DWI with STIR-EPI. Ability of detecting lymph nodes between conventional MRI and STIR-EPI-DWI was compared, and the difference of apparent diffusion coefficient (ADC) value between metastatic lymph node and normal lymph node was analyzed.</p><p><b>RESULTS</b>DWI was more sensitive in detecting lymph node than conventional MRI. ADC value of metastatic lymph node (0. 766 +/- 0. 119) x 10 (-3) mm(2)/s was significantly lower than that of normal lymph node (0. 975 +/- 0. 179) x 10 - mm2/s (P < 0. 01).</p><p><b>CONCLUSION</b>As a new MRI imaging technique in detecting cervical lymph nodes, diffusion weighted imaging ( DWI) with short TI version recovery-echo planar imaging ( STIR-EPI) sequence is more reliable and sensitive than conventional MRI imaging, providing an alternative way to differentiate benign lymph nodes from malignant ones.</p>

Imaging diagnosis of aneurysmal bone cyst secondary to giant cell tumor / 中华放射学杂志

Objective To improve recognition and imaging diagnosis of aneurysmal bone cyst secondary to a giant cell tumor.Methods To collect the dates of 12 patients with aneurysmal bone cyst secondary to a giant cell tumor were proved by operation and pathology from January 2003 to October 2006. Analyzed and summarized their imaging manifestations and correlation with pathohistology.Results Six lesions were located in epiphysis and metaphysic regions of long bone.Six lesions were located in pelvis.All cases showed a cystic lesion with expanded and osteolytic,eccentric 10 cases and centric 2 cases.Four cases display trabeculate,the margin is well define with a rim of bone sclerosis in 2 cases.Magnetic resonance imaging(MRI)scans were available in 10 patients.All case showed cystic,dilated lesions with solid areas. Eight cases manifested single or multitude solid nodules in big cystic wall.Two cases appeared solid masses with multitude cysts.The sign of multitude fluid-fluid level,best seen on T_2-weighted images,was present in all patients.Seven cases emerged soft-tissue masses.MR found indicative of large amounts of hemosiderin in one cases.Eight cases were examined by spiral CT with plain scanning and enhancement scanning. Reconstructed image were CTA and 3D-MPR(three dimensions multiplanar reconstruction)imaging.All cases showed cystic,dilated lesions with solid areas.The sign of multitude fluid-fluid level was present in 6 patients.The solid areas and cystic-wall of lesions showed contrast enhancement in 8 patients.3D-MPR imaging showed supply blood vessel of tumors in 3 cases.Arteriovenous malformation did not found in all patients.The surgeons'operative findings and the gross specimens were studied in all patients.All lesions were composed of solid areas and cystic areas.The diagnosis of pathology were ABC with GCT(grade Ⅱ)in 10 cases and ABC with GCT(grade Ⅲ).Conclusion Aneurysmai bone cyst secondary to a giant cell tumor is not rare.Adequately recognizing the pathologic basis of ABC,and selecting imaging techniques correctly (X-ray and MRI,or X-ray and CT)is especially important to diagnose a giant-cell tumor with secondary aneurysmai bone cyst.When an eccentric,expanded,lytic tumor with a cystic-solid lesion in epiphysis of long bone or pelvis shows multiple fluid levels,a giant-cell tumor with secondary aneurysmai bone cyst components should be sufficiently considered.

Evaluation of brachial plexus injury by MRI / 中华放射学杂志

Objective To evaluate the diagnostic value of MRI in brachial plexus injury.Methods Total 98 patients with brachial plexus injury were examined by MRI before operation.Fifty-four of 98 patients MR imaging were obtained by 0.5 Tesla scanner and other 44 patients were obtained by 1.5 Tesla scanner.The scanning sequences include: SE T_1WI,T_2WI,FFE T_2WI and T_2WI SPIR. Exploration of the supraclavicular plexus was carried out and the MR imaging were compared with the operative finding in 63 patients.Thirty-five patients who had not surgery were followed-up.Results MR imaging found pre-ganglionic injuries in 45 patients and post-ganglionic injuries in 56 patients.Pre-and post-ganglionic injuries simultaneously in 16 patients among them.MR imaging can not find injury sings in 13 patients.The positive rate was 86.73%.MR imaging finding of pre-ganglionic injuries include:(1) Spinal cord edema and hemorrhage,2 patients (4.44% ).(2)Displacement of spinal cord,17 patients (37.78%).(3)Traumatic meningoceles,37 patients (82.22%).(4)Absence of roots in spinal canal, 25 patients(55.56% ).(5)Scarring in the spinal cnanl,24 patients (53.33%).(6)Denervation of erector spine,13 patients (28.89%).MR imaging finding of post-ganglionic injuries include:(1)Trunk thickening with hypointensities in T_2WI,23 patients (41.07%).(2)Nerve trunk complete loss of continuity with disappeared of nerve structure,16 patients (28.57%).(3)Continuity of nerve trunk was well with disappearance of nerve structure,14 patients(25.00%).(4)Traumatic neurofibroma,3 patients (5.36%).Conclusion MR imaging can reveal Pre-and post-ganglionic injuries of brachial plexus simultaneously.MR imaging is able to determine the location (pre-or post-ganglionic)and extent of brachial plexus injury,provided important information for treatment method selection.