【Abstract】ObjectiveTo evaluate the value of MR imaging with a contrast-enhanced multi-phasic isotropic volumetric interpolated breath-hold examination (VIBE) in diagnosis of primary liver carcinoma. MethodsThirty-two consecutive patients with surgical-pathologically confirmed 42 foci of primary carcinoma of liver underwent comprehensive MR examination of the upper abdomen, routine two-dimensional (2D) T1WI and T2WI images were acquired before administration of Gd-DTPA for contrast enhancement. Then, contrast-enhanced multi-phasic VIBE was acquired followed by 2D T1WI images. The lesion appearances on hepatic arterial, portal venous and equilibrium phases of VIBE sequence were carefully observed along with delineation of hepatic arterial and portal venous structures. The lesion detection rates and lesion characterization ability were compared among various MR sequences. Results33(78.6%), 30(71.4%), 38(90.5%) and 42(100%) foci were displayed respectively on T2WI, non-enhanced T1WI, enhanced T1WI and enhanced 3D-VIBE images (P＜0.05). The hepatic arterial anatomy of 30 patients （93.8%） and the portal venous structure of 31 patients （96.9%） were clearly depicted on enhanced 3D-VIBE images. Using MIP and MPR reconstruction techniques, the feeding arteries of 14 foci and draining vein of 12 foci were clearly displayed.ConclusionHigh-quality 3D-VIBE images are not only better than 2D images in lesion detection and characterization for primary liver carcinoma, but also able to provide much more information about hepatic vascular anatomy.
ObjectiveTo investigate the value of magnetic resonance (MR) imaging in the assessment of bile duct complications after cholecystectomy. MethodsFifty patients of having bile duct complications after cholecystectomy underwent MR imaging and had some positive manifestations. The indication for cholecystectomy was symptometic cholelithiasis in all cases. MR imaging was performed with a 1.5T clinical imager including all of the sequences of: ①T1 weighted imaging (T1WI) was performed in transverse and coronal plane before and after gadolinium-enhanced. ②T2 weighted imaging (T2WI) was performed in transverse plane. ③A true fast imaging with steadystate precession sequence (True fisp) was performed in coronal plane. ④MR cholangiopancreatography was also obtained. ResultsThe bile duct complications after cholecystectomy including: 22 cases of cholelithiasis, 15 cases of chronic cholangitis with or without bile duct abscess. Bile duct strictures or abruption at the confluence of hepatic and common bile duct in 6 and 3 cases respectively. Tumors of bile duct or pancreas in 9 cases. The other complications after cholecystectomy including bile leak with choleperitonitis and/or biloma and acute pancreatitis.ConclusionMR imaging was a valuable method for the assessment of bile duct complications after cholecystectomy. MR imaging could assess the etiology of bile duct complications. If there were bile duct obstruction, MR imaging could assess the location and the severe of obstruction. For bile duct or pancreatic tumors, MR imaging could assess the areas of tumor infiltration and resection and was helpful to select treatment methods. Before lapatoscopic cholecystectomy, the overall and careful imaging assessment for bile duct and gallbladder and its adjacent hepatic tissue and pancreas so to avoid missing the relative tumors.
This study aims to explore the potential of polyaspartic acid grafted dopamine copolymer (PAsp-g-DA) chelated Fe3+ for magnetic resonance imaging (MRI) visual photothermal therapy. Polyaspartic acid grafted copolymer of covalently grafted dopamine and polyethylene glycol (PAsp-g-DA/PEG) was obtained by the ammonolysis reaction of poly succinimide (PSI), and then chelated with Fe3+ in aqueous solution. The relaxivity in vitro, magnetic resonance imaging enhancement in vivo and photothermal conversion effect at 808 nm were investigated. The results showed that polymeric iron coordination had good near-infrared absorption and photothermal conversion properties, good magnetic resonance enhancement effect, and good longitudinal relaxation efficiency under different magnetic field intensities. In summary, this study provides a new magnetic resonance visual photothermal therapeutic agent and a new research idea for the research in related fields.
Objective To explore the MRI features of juvenile-onset ankylosing spondylitis (JoAS) for improving the level of diagnosis and therapy. Methods MRI findings of JoAS in 25 patients confirmed by clinical and laboratory results between October 2010 and September 2014 were retrospectively analyzed. Results There were a total of 67 locations of lesion in the 25 cases, including 19 in sacroiliac joint, 21 in hip joint, 6 in ischial tuberosity, 6 in crista iliaca, 9 in knee joint, 4 in ankle joint, and 2 in foot. MRI showed 63 locations with bone marrow edema, 36 with joint effusion, 26 with bone destruction, and 19 with enthesitis. Conclusions Bone marrow edema is the most common MRI manifestation of JoAS, and the main bone destruction is middle axis joint. MRI is sensitive but not specific to lesions, so differential diagnosis is needed and helpful.
Objective To explore the program for calculating the necrotic articular surface area (NASA) and the ratio of NASA to whole articular surface area (WASA) of osteonecrosis of the femoral head (ONFH), to verify the accuracy of this calculation and to predict the collapse of the femoral head clinically using this program. Methods From June 2001 to June 2003, The specimens of the necrotic femoral head from eight patients (13 hips) were obtained by total hip arthroplasty. The magnetic resonance imaging (MRI) was taken in all patients before operation. According to a series of T1-weight pictures, the NASA and the ratio of NASA to WASA were calculated by designing program. The specimens of the necrotic femoral head were sawed into lays similar to MRI pictures using the coordinate paper stick on the auricular surface, the data processing were done by analytic instrument for pictures. The data of both were analyzed statistically by software SPSS 10.0 edition. The NASA and the ratio of NASA to WASA were calculated on MRI in ARCO Stage Ⅰ, Ⅱ 16 patients (25 hips) with non-operation. Follow-up was done to the patients with collapse of the femoral head and to the patients with no collapse for at least 24 months. The data were compared in collapse group and non-collapse group. Results There were no significant differences between MRI pictures calculation and specimens measurement (NASA: 0.412, ratio of NASA to WASA: 0.812, Pgt;0.05). Of the 25 hips followed up, collapse occurred in 17 hips. NASA was 31.06±8.10 cm2, (95% CI: 26.58 to 35.55)，the ratio of NASA to WASA was 58.91%±15.11%, (95% CI: 51.14to 66.68). No collapse appeared in 8 hips. NASA was 14.16±9.32 cm2(95% CI: 6.04 to 21.95), the ratio of NASA to WASA was 29.48%±19.76%(95% CI: 12.97to 45.99). The ratio in the patients with collapse was beyond 33%. Conclusion The NASA and the ratio of NASA to WASA in patients withONFH can be accurately calculated with the MRI pictures. The possibility of collapse can be predicted by this method. As it is complicated in operation, improvement should be made in order to put itinto clinical use.
Objective To evaluate the diagnostic value of magnetic resonance cholangiopancreatography (MRCP) in obstructive jaundice. Methods Forty eight consecutive patients with obstructive jaundice were examined by MRCP, all results were testified during and /or after operation. Results Different causes of obstruction had their own characteristic manifestations. Level of obstruction was accurate in 100%, the accuracy in distinguishing obstructive causes was 93.8%. Conclusion MRCP is quite effective, safe and reliable in diagnosis of obstructive jaundice.
Objective To determine the safety of the fetal olfactory ensheathing cell(OEC) transplantation in patients with chronic spinal cord injury (SCI) by examination of the magnetic resonance imaging (MRI). Methods A prospective clinical study involving 16 patients with chronic SCI was designed to investigate the feasibility and biological safety of the fetal OEC transplantation in treatment of SCI. The olfactory bulbs from the 3-4-month-old aborted human fetuses following the strict ethical guidelines were harvested and trypsinized down to single fetal OEC. These cells were then cultured for 12-17 days and were prepared for a clinical use. From November 2001 to December 2002, 16 patients with chronic SCI were randomly enrolled. The patients suffered from SCI for1.5-8 years (average 4-3 years) after the injury. The suspension (50 μl) containing about 1×106 fetal OECs was transplanted by an injection into the patients’ spinal cords above and below the injury site. All the patients were assessed before thetransplantation and were followed up with MRI for 29-42 months (average 38 mon)after the transplantation. Results No cell-related adverse effects were observed in any patient during the followup period. The follow-up with MRI did not reveal any development of optic glial tumor, tumor-like mass, new hemorrhage,edema, expanding cyst, new cyst formation, infection or disruption of the neuralstructure in the transplant site of all the patients. Conclusion This is the first clinical study demonstrating the long-term safety of theOEC therapy for SCI. The results indicate that our protocol is feasible and safe in treatment of patients with chronic SCI within 38 months after the injury. Although the size of the samples for our study was not big enough, the positive results of the study have encouraged us to make a further research in this field.
ObjectiveTo compare the clinical efficacy of glucosamine hydrochloride and diacerein for patients with knee osteoarthritis and the MRI variation. MethodsBetween January and June 2014, 90 patients with knee osteoarthritis were randomized into three groups: group A (treated by glucosamine hydrochloride), group B (treated by diacerein) and group C (treated by both glucosamine hydrochloride and diacerein). The score of Western Ontario and McMaster Universities (WOMAC) index of osteoarthritis, MRI cartilage injury Recht grading and the curative effects for bone marrow edema, joint cavity effusion and meniscus injury were compared before and after the treatment. ResultsThe scores of WOMAC after treatment in all the groups were improved, while the therapeutic effect of group C lasted longer when medical treatment suspended. The number of articular surface with different degrees of cartilage injury showed no statistically significant change in all three groups (P ＞ 0.05) . The state of bone marrow edema and joint cavity effusion were improved with a statistically significant difference in all groups (P ＜ 0.05) . Patients with lateral meniscus degeneration in group A and patients with medial meniscal tear in group B both increased with statistically significant differences (P ＜ 0.05) . However, in group C, patients with lateral meniscus degeneration or meniscal tear decreased with statistically significant differences (P ＜ 0.05) . ConclusionsThe treatment for osteoarthritis by glucosamine hydrochloride is effective, and the curative effect lasts longer when treated by both glucosamine hydrochloride and diacerein. Glucosamine hydrochloride ameliorates the bone marrow edema and joint cavity effusion. Treatment together with diacerein leads to a better therapeutic effect for patients with meniscus degeneration, yet further studies are needed to prove its effects in ameliorating cartilage injury.
The portable light-weight magnetic resonance imaging system can be deployed in special occasions such as Intensive Care Unit (ICU) and ambulances, making it possible to implement bedside monitoring imaging systems, mobile stroke units and magnetic resonance platforms in remote areas. Compared with medium and high field imaging systems, ultra-low-field magnetic resonance imaging equipment utilizes light-weight permanent magnets, which are compact and easy to move. However, the image quality is highly susceptible to external electromagnetic interference without a shielded room and there are still many key technical problems in hardware design to be solved. In this paper, the system hardware design and environmental electromagnetic interference elimination algorithm were studied. Consequently, some research results were obtained and a prototype of portable shielding-free 50 mT magnetic resonance imaging system was built. The light-weight magnet and its uniformity, coil system and noise elimination algorithm and human brain imaging were verified. Finally, high-quality images of the healthy human brain were obtained. The results of this study would provide reference for the development and application of ultra-low-field magnetic resonance imaging technology.
The gradient field, one of the core magnetic fields in magnetic resonance imaging (MRI) systems, is generated by gradient coils and plays a critical role in spatial encoding and the generation of echo signals. The uniformity or linearity of the gradient field directly impacts the quality and distortion level of MRI images. However, traditional point measurement methods lack accuracy in assessing the linearity of gradient fields, making it difficult to provide effective parameters for image distortion correction. This paper introduced a spherical measurement-based method that involved measuring the magnetic field distribution on a sphere, followed by detailed magnetic field calculations and linearity analysis. This study, applied to assess the nonlinearity of asymmetric head gradient coils, demonstrated more comprehensive and precise results compared to point measurement methods. This advancement not only strengthens the scientific basis for the design of gradient coils but also provides more reliable parameters and methods for the accurate correction of MRI image distortions.