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 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.

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 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 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.

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 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.

BACKGROUND: Sonography is believed by many scholars to be sensitive for the detection of hepatic arterial thrombosis and stenosis, but it is difficult to show the anastomotic vascular stenosis. MR angiography is better than sonography in the display of vascular anatomy and the diagnosis of various vascular complications after liver transplantation.OBJECTIVE: To evaluate the role of MR angiography (MRA) in the display of vascular anatomy and the diagnosis of various vascular complications after liver transplantation.DESIGN: Contrast trial observation.SETTING: Medical Imaging Center of Nanfang Hospital, Southern Medical University.PARTICIPANTS: Eleven adult male patients had undergone liver transplantations at Nanfang Hospital of Southern Medical University between January 2004 and December 2006. They ranged in age from 40 to 58 years, average 49 yeas. Original causes of liver failure in the study group included cirrhosis (n =9) and primal hepatic carcinoma (n =2) diagnosed by pathohistological methods. And 9 cases had undergone orthotopic liver transplantations while 2 cases with piggy-back liver transplantation.METHODS: Eleven consecutive adult patients underwent MR imaging examinations after orthotopic liver transplantation using a breath-hold 2D True Fast Imaging with Stead-state Precession and Fast Low Angle Shot. MR triphasic contrast-enhanced 3D imaging was also performed. Enhancement scan: A final gadolinium-enhanced axial and coronal T1WI spin-echo sequence with spectral fat saturation was performed after completion of the MRA. The vascular diameter stenosis was calculated according to S (S=[(D-d)/D]×100%) by ECST method, d as the inner diameter of the most obvious stenosis while D as normal diameter. Degree of stenosis: normal as S 0-30%, mild stenosis as S 31%-50%, moderate stenosis as S 51%-85%, and severe stenosis as S 86%-100%. Then the imaging findings after liver transplantation were analyzed. Meanwhile the sonography was performed.MAIN OUTCOME MEASURES: ① MR Image analysis of vascular anatomy and vascular complications after liver transplantation.②Normal findings after liver transplantation by using sonography.RESULTS: All 11 patients were involved in the result analysis.①MRA: The anastomosis of hepatic artery, portal vein and inferior vena cava were smooth in 3 cases. The high signal intensity was seen around portal vein at T2WI in 1 case with a shorter interval after transplantation and persisted 3 weeks. In 1 case, the caliber of the donor portion was smaller than the recipient portion. Among other 8 cases, hepatic artery complication included hepatic artery winding in 2 cases and aneurysm formation of donor's hepatic artery in 2 cases, but the twig of the hepatic artery was normal. Mild Portal vein stenosis at the anastomosis was found in 2 cases, caused by the different calibers of the donor portion from the recipient portion, but the inter-hepatic branches of the portal vein were normal. Clubbed dilatation of hepatic veins end-brush was depicted in 2 cases whose inferior vena cava at the anastomosis was not stenosis. Inferior vena cava thrombosis was found in 1 case. The thrombus displayed the low signal intensity in the high signal intensity of inferior vena cava. By follow-up examination, the degree of clubbed dilatation of hepatic veins end-brush reduced after half a year and inferior vena cava thrombosis disappeared by treatment. ②Sonography: By ultrasound examination, 1 case who had hepatic artery winding combining to aneurysm formation of donor's hepatic artery was discovered just hepatic artery winding. In 2cases that had mild portal vein stenosis at the anastomosis, 1 case was diagnosed normal while the other was not affirmed. The clubbed dilatation of hepatic veins end-brush was not depicted. The others were same as MRI diagnosis.CONCLUSION: Dynamic enhanced 3D MRA imaging can provide a comprehensive assessment of vascular anatomy in most recipients of liver transplants, and is an accurate and quick method to diagnose the vascular complication after liver transplantation.

Objective To resolve the sharing of the images which are dispersed in multiple mini-PACS in one hospital or in the distributed PACS in the different hospitals.Methods The grid technology and the medical image network were integrated to research some key technologies on a medical image storage grid.Results Basing on the services provided by grid and considering the hospital's situation,two layers architecture of storage grid that was adapted with the sharing character of the medical information were put forward.Using the services provided by the storage grid,the dynamic storage extension was realized.Conclusion The medical image storage grid can integrate multiple storage systems in the image network.It supports the effective usage of the storage system and transparent accessing for users.

Objective To evaluate the MRI features of osteosarcoma.Methods 38 cases of osteosarcoma proved pathologically were retrospectively analyzed.All of them were examined by plain MRI scan,25 cases were examined by enhanced scan.Results The diagnostic accuracy of osteosarcoma of MRI was 93.9%.There were 30 cases of the extension into the medullary cavity,18 cases of soft tissue mass,10 cases of the destruction in epiphysis and 4 cases of the invasion in articular cartilage,especially T2 weighted STIR image and enhanced MRI scans were advantageous in showing the images mentioned above and in judging of the change after treated.Conclusion MRI is very important in diagnosis and clinical therapy of osteosarcoma.