Objective To explore the susceptibility weighted imaging (SWI) appearance of paramagnetic and diamagnetic materials, its imaging theory, and its value of differential diagnosis from their appearance. Methods The diamagnetic and paramagnetic phantom were made and the X-Y axial SWI phase image of phantom then was obtained. Twenty-eight cases of intracerebral calcium and 21 cases of hemorrhage examined with MRI scan and CT scan were retrospectively investigated. The appearance of calcium and hemorrhage on SWI were analyzed and compared with their appearance on CT and conventional MRI. Results Phantom experiment indicated that the equator plane scan of diamagnetic sphere showed high signal in centre surrounded by low signal ring and high signal in two poles of sphere along Z axis of main magnetic field. The paramagnetic sphere appeared the opposite appearance of diamagnetic sphere with centre low signal surrounded by high signal ring in equator plane and low signal in two poles of sphere along Z axis of main magnetic field. The SWI manifestations of 4 cases of intracerebral sphere or sphere-like calcification ( chorioidal calcification) and 9 cases of sphere or sphere-like hemorrhage(2 cases of traumatic hemorrhage, 1 case of hypertension related basal ganglion hemorrhage, 4 cases of metastasis hemorrhage and 2 cases of cavernous hemangioma hemorrhage)were consistent with diamagnetic and paramagnetic sphere phantom respectively. Four cases of calcification in basal ganglion showed the mixed high and low signal. Seven cases of irregular calcification ( neoplastic calcification) aside from basal ganglion appeared complex appearance, though mainly in high signal. Other sphere or sphere-like calcification aside from basal ganglion ( 14 cases of pineal calcification, 4 cases of chorioidal calcification, 2 cases of cerebral cysticercosis calcification and 1 case of neoplastic calcification ) showed markedly high signal. Nine cases of intracerebral iobular hemorrhage (2 cases of hypertension related basal ganglion hemorrhage, 4 cases of unknown casual hemmorrhge and 3 cases of cavernous hemangioma hemorrhage) displayed a multiple concentric circle appearance, other 3 hemorrhage showed complex appearance, though mainly in low signal. Ten cases of calcification had no specific appearance on T1 WI and T2WI. Conclusion Phase image of SWI is helpful in differentiating intracerebral diamagnetic from paramagnetic materials and it has some advantage in detecting calcification over T WI and T2 WI.

Objective To investigate MRI features of dysembryoplastic neuroepithelial tumor(DNT).Methods The MR images of ten cases with surgically and pathologically proved DNT were retrospectively reviewed.Results MR imaging showed cystic component with mural nodule in 6,mainly cystic component with septa in 3.The solid components of the tumors were long T_1 and long T_2 signal intensity,the cystic components were even longer T_1 and T_2 signal intensity which resembled the signal of cerebrospinal fluid.Mild enhancement could be found at the intra-tumoral solid nodule or septations after injection of constrast medium but the cystic component did not show any enhancement.No peri-tumoral edema and mass effect were found in most cases.Conclusion DNTs are of some special features on the MR images,the diagnosis can be exactly done before operation if MRI features in combination with clinical data of the patients.

Objective To study CT and MRI value in diagnosis of osteoblastoma,in order to achive more information about the disease. Methods The clinical,CT,MRI and histological data of 12 patients with osteoblastomas. Results(1)There were 6 patients wereexamined by CT,the lesions showed mainly lytic with varying degrees of matrix mineralisation,and mild adjacent reactive sclerosis;(2)10 patients were examined by MRI(included 4 patients who have been examined by CT),the lesions presented mixed signal intensity with compart,slightly low and intermediate signal intensity on T_1-weighted images,high signal intensity on T_2-weighted images were found in 9 cases and mainly low signal intensity was found in 1 case.8 cases showed clear low signal intensity surrounding the lension borh on T_1 and T_2,2 cases showed blurry high signal in the adjacent tissue;(3) The tumors presented moderate enhancemen with low dense area inside the lesions after injection of contrast media. Conclusion Osteoblastomas have classical features on CT,while show no characteristic appearances on MRI.

Objective To explore the imaging features and pathological characteristics of fibrous dysplasia of craniofacial bone. Methods 42 cases with fibrous dysplasia of craniofacial bone confirmed surgically and pathologically were retrospectively analyzed. Results There were 35 cases with single bone involved and 7 cases with poly-bone involved. On CT images, the lesions appeared as glass-like change(79.3%). The main pathological components of the lesion were fiber and fiber-like tissue, which were low signals on both T_1 WI and T_2 WI, and the signal intensity was changed with the accompanied by hemorrhage, necrosis or cystic degeneration. Conclusion CT and MRI are the effective imaging modality in diagnosis of fibrous dysplasia of craniofacial bone.

Purpose to explore a CT classflication of hepatic echinococcal cysts and its clinical application. Materials and Methods reviewed 85 patients who had underwent CT scan in our hospital from 2008-01～2009-12.The CT classification was made according to WHO classification and the CT appearances were analyzed retrospectively.Results Among the lesions,there were 16 CL type,appeared as a unilocular round cyst without wall.15 CE1 type,appeared as a unilocular cyst with a smooth uniform wall.28 CE2 type,appeared as a fluid collection with septa (honeycomb sign),and 6 CE3 type,CT appeared as a fluid collection with a split wall,10 CE4 type,CT appeared as a fluid collection with a split wall (water-lily sign).36 CE5 type,CT appeared as a calcified mass.Conclusion CT classification according to WHO classification for cystic echinococcosis is using to differentiate it from other liver cystic lesions,such as simple cyst and abcess,and is essential when planning clinical treatment.

Objective To evaluate the characteristics of CT, MRI, PET and histopathology of brain radiation injuries following radiotherapy for nasopharyngeal carcinoma. Methods We reviewed the imaging records of 71 patients with brain radiation injuries following radiotherapy for nasopharyngeal carcinoma examined over a 10 year period. Results The radiation injury lesions occurred in the temporal lobes, brain stems or cerebella. Their CT appears were homogeneous or heterogeneous density. If the lesions situated in temporal lobes, they presented as "finger like" hypointensity. Twenty three patients(29 lesions) undenwent contrast enhanced CT scan, 86.2 percent(25/29)of the lesions showed no enhancement. MRI demonstrated prolonged T 1 and T 2 relaxation time of the injured tissue, they might showed homogeneous or heterogeneous signal intensity. MR enhanced T 1WI were performed in 20 cases(29 lesions),and 65.5 percent(19/29)of the lesions presented "Flower lace" enhancement. Two patients were carried on PET scan. One patient′s PET appearance is similar to the CT or MRI finding. Resections and histopathologic observations of temporal lobes′ lesions were performed on 3 cases, which showed cerebral necrosis. Conclusion (1) MRI plain or contrast enhanced scan is more sensitive than that of CT or PET. (2)The heterogeneous signal intensity on T 1WI and T 2WI represent necrosis,and all are located in the radiation field. (3)"Flower lace" enhancement on contrast MRI is the characteristic of brain radionecrosis. (4)PET may serve as a complementarity in the diagnosis of radiation induced injuries.

Objective To summarize MR manifestations of cerebral arteriovenous malformations (AVMs), and to evaluate the accuracy of MR angiography in determining cerebral AVMs’ aspects. Methods Thirty-six cases of cerebral AVMs were analyzed comparatively between MRA and DSA in sizes, feeding arteries and draining veins. Results Cerebral AVMs were appeared in every part of brain. MRI showed honeycombed and linear flow-void low intensity signal in lesion area, showed flow-void signal of expanded thickening vessels, and showed cerebral atrophy or fraction surrounding the lesions. MRA showed that the sizes of most AVMs were 2～5 cm, that the feeding arteries originate from the expansion of original feeding arteries of these areas, that the draining veins drain from the lesions into the surrounding veins or sinuses. The numbers of these vessels were related positively to the sizes of lesions. The differences in showing AVMs between MRA and DSA were that the sizes of lesions on MRA were more than those on DSA, and the numbers of draining veins on MRA were more than those on DSA. Conclusion MRA may show all signs of AVMs, and is not less than, or superior to DSA in their diagnosis. MRI may play important roles in the examination and the diagnosis of cerebral AVMs.

Objective To evaluate the clinical significance and value of MRI for the diagnosis of the meniscus and ligament injury of the knee joint. Methods 27 patients were put under MRI examinations with 1.5 T unit(Magnetom Vision plus, SIEMENS)and confirmed by surgery or arthroscopy. In all patients, the sagittal and coronal multiplane scan was performed with 4mm section thickness. The posterior cruciate ligament (PCL) angle and PCL curvature index were measured in 8 patients with anterior cruciate ligament (ACL) tears and in 22 patients with ACL normal. The results of measuring were statistically analyzed. Results The accurate diagnosis of MRI was 18 of 24 patients (62.07%) and 24 of 31 cases with meniscus injury (77.42%). On MRI, the signs of meniscus injury were as follows: firstly, the linear high signal intensity inside meniscus was abnormal. Secondly, the size of meniscus diminished and the inner edge was pointless. The third, the triangle configuration of meniscus disappeared.The fourth, the lower or superior margin of meniscus appeared as wavelike configuration. The fifth,the distance from outer side of meniscus to articular capsule increased. Only 5 in 9 patients with ACL tears were exactly diagnosed and the accuracy ratio was 55.56%. There were remarkable statistical differences between the ACL tears group and ACL normal group in the results of (PCL) angle and PCL curvature index(P

[Objective]To explore a new technique of prefabricating internal plate.[Method]Three-dimensional reconstruction of the well-liking shinbone was performed by MSCT scanning and the length and shape of the catagmatic shinbone for operation was measured on well-liking shinbone.The shinbone curve was depicted using a self-designed skeletal curve-depicting.Then shape of the material for internal fixation was determined.[Result]The length and shape of the shinbone curve was accurately measured.The physiological curve of the shinbone was depicted.Then shape of the material for internal fixation was determined.[Conclusion]Three-dimensional well-liking shinbone reconstruction with MSCT and measurement facilitates the determination of the optimal length and shape of the internal fixation material to enhance the attachment between the material and the bone surface and consequently the therapeutic effects.One case's length and shape of internal fixation was dissatisfactory for hyperplasia of bone.But the length and shape of internal fixation has basal shape.

Objective To solve the new problems for quality assurance of PACS which imported by the use of PACS.Methods The medical imaging quality control system used between imaging modality and image acquisition gateway was designed.Results The medical imaging quality control system could partially solve the problem for quality assurance of PACS.Conclusion With the use of medical image quality control system,wrong or low quality image can be found and modified earlier.Therefore,the veracity of medical information and medical image of PACS can be improved farther.