Objective To evaluate the value of apparent diffusion coefficients (ADCs) in the diagnosis of malignant bone neoplasms.Methods Eighteen cases with consecutive primary malignant bone neoplasms of the knee were prospectively enrolled in the study. Each patient had a controlled preoperative MRI including a SSEPI-DWI sequence. With the help of a pathologist, spatially localized histological sampling study of the postoperative specimens was performed. ADCs of viable tumor (intra- and extraosseous part), peritumoral edema (including soft tissue edema and intramedullary edema), and tumor necrosis of the neoplasms confirmed by spatially localized histological sampling or following up were calculated and compared.Results Mean ADCs of viable tumor, peritumoral muscle edema, peritumoral marrow edema, tumor nerosis, normal muscle, and normal marrow were (1.181?0.236)?10 -3mm2/s (intraosseous part)/(1.158?0.259)?10 -3mm2/s (extraosseous part), (2.347?0.233)?10 -3mm2/s, (1.997?0.119)?10 -3mm2/s, (2.230?0.208)?10 -3mm2/s, (0.486?0.313)?10 -3mm2/s, and (0.483?0.288)?10 -3mm2/s, respectively. Statistical differences were significant among all these tissues (F=153.131, P=0.000). The ADCs of viable tumor were higher than that of normal tissues (P

Objective To study the correlation between bone marrow edema (BME), the amount of joint fluid and clinical symptoms in order to strengthen further understandings about clinical significance of BME in osteonecrosis of the femoral head (ONFH). Methods Fifty-seven patients (91 hips) with ONFH proved by clinical follow-up or pathology were examined by conventional radiography, 1.5 T MRI, and radionuclide imaging. BME, necrotic area, and joint fluid were analyzed respectively in ONFH with pre- or post-collapse of the femoral head and different MR signal intensities within necrotic area.Results ①The characteristic “line-like sign” appeared on MRI in 88 of 91 affected hips, and BME was seen in the distal zone away from line(s) in 61 hips, extending to the femoral neck and intertrochanteric region. ②The ratio of the occurance of BME in the collapse was greater than that in noncollapse, and in mixed signals within necrotic area without collapse greater than pure fat-like signal (P0.05), and both were greater than noncollapse without BME (P

0.05). Conclusion There is no significant correlation between MVD and perfusion. Neovascularizaton and perfusion are highly presented in early colorectal carcinoma. SCT may be more suitable for assessing tumorigenesis than histological MVD technique.

Objective To probe the feasibility of single dose contrast enhanced magnetic resonance aortography(CEMRA) and evaluate its value in clinical application. Methods Transit time(TT) test and duration of peak enhancement of aorta(DPE) test in 28 healthy adults were performed. With 2 different injection rate of Gd DTPA at 2 ml/s and 3 ml/s, the TT,peak signal intensity of aorta(SPE),DPE and the interval between DPE and the time of injection(?T) were measured and compared. Two groups of healthy volunteers(each 10) underwent three diamentional fast imaging in static procession sequence (3D FISP) CEMRA with standard dosage of Gd DTPA with the injection rate at 2 ml/s and 3 ml/s respectively. The signal/noise ratio(SNR) of the source images and the image quality of CEMRA of both groups were compared. Fifteen patients with aortic disease did the same study as the voluteers with the injection rate only at 3 ml/s. Results With the injection rate of 2 ml/s and 3 ml/s,the TT,SPE,DPE,?T and the SNR of CEMRA in two groups were significantly different( P

Objective To evaluate the value of MRI categorization of cholesteatoma of the skull base (CSB) and its MRI diagnostic characteristic Methods The CT, MRI and pathological data of 15 patients with CSB were reviewed The CSBs were categorized into type I and type II based on the difference of signal intensity on T 1 weighted image, and the differences between the two types of CSB were compared in the aspects of CT and MRI findings and osseous encroachment of the skull base Results Extremely high signal intensity on T 2 weighted image being similar to that of cerebrospinal fluid, and unenhanced tumor parenchyma on enhanced T 1 weighted image were noted in the 15 cases of CSB Of the 15 CSBs, 6 were categorized as type I and the other 9 as type II on the basis of the difference of the signal intensity on T 1 weighted image The 6 CSBs of type I, located in the prepontine and cerebellopontine angle cisterns, appeared as homogeneous hypoattenuating on CT scan and homogeneously decreased signal intensity on T 1 weighted image coupled with unenhanced tumoral capsule and relatively normal skull base The tumor parenchyma of this type was consisted of homogeneous cholesterol crystal The 9 CSBs of type II, located in unilateral floor of middle or posterior cranial fossa, were demonstrated as mixed density on CT scan and mixed signal intensity on T 1 weighted image, of which 4 presented as decreased signal intensity scattered with increased signal intensity, 5 largely as increased signal intensity The 9 cases were noted with enhanced tumoral capsule and marked osseous encroachment of the skull base, and the parenchyma of which was mainly comprised of keratinized epithelia and proteins Conclusion The categorization of CSB into type I and type II is sensible, which reflects the distinction in both histopathology and biological behaviour between the two types of CSB and plays an important role in guiding MRI diagnosis of CSB The MRI diagnostic characteristic of CSB includes the versatile signal intensity on T 1 weighted image, marked increased signal intensity on T 2 weighted image, unenhanced tumor parenchyma and type related osseous encroachment of the skull base

Objective To investigate the effect of imaging parameters and postprocessing methods on the quality of MR imaging of short T2 components with 3D ultrashort TE (UTE) double echo pulse sequence. Methods 3D UTE double echo pulse sequence was performed on dry human femoral specimen and the tibial diaphyses, knee joints, and tendons of ankles of a group of healthy volunteers. To investigate the effect of different trajectory delays of the imaging system(-6, -3, -2, - 1,0, 1,2, 3 s), different flip angles(4°, 8°, 12°, 16°, 20°, 24°), different TEs (0. 08, 0. 16, 0. 24, 0. 35 ms)and different postprocessing methods(difference imaging of subtracted volume and non-volume UTE)on the 3D UTE MR imaging quality, the SNR and CNR were calculated and compared, and the artifacts of the images were analysed. Results The cortical bone, periosteum, tendon and meniscus showed high signal intensity on the images of UTE pulse sequence. The best SNR was acquired with 2 s trajectory delay. The best flip angle was 8° to 12° for the human UTE imaging in vivo. The highest CNR was obtained from the TE of 0. 08 ms. The longer the TE was, the more artifacts appeared. The SNR of difference imagewas improved when image subtraction was performed afer multiplanar reconstruction (MPR) of the primary double echo images.Conclusions The short T2 components show high signal intensity on the MRI of 3D UTE double echo pulse sequence. The imaging quality can be improved by shortening TE, using appropriate flip angle and performing subtraction for difference image after MPR of the primary double echo images.

Objective To determine the optimal sequences and scan parameters of Brachial Plexus MRI.Methods Eighteen volunteers were underwent conventional MRI and echo planar imaging scanning. The images acquired were compared with the standard anatomical pictures. Results Ventral rami, ganglion, trunks, cords and some peripheral nerves of brachial plexus were demonstrated very well by echo planar imaging with the post-processing techniques such as MIP, thin slice MIP and MPR.In 18/18 cases the postganglions on both sides and 17/18 cases the preganglions of brachial plexus on both sides could be visualized in EPI pre-processed and post-processed images.Conclusion Echo planar imaging is an effective technique of accurately displaying brachial plexus and adjacent structures. It has potential value in the diagnosis and treatment of brachial plexus diseases. It is also a potential technique to demonstrate other peripheral nerves accurately.

Objective To analyze the MRI characters of Charcot joint, and to evaluate the diagnostic value of X-ray, CT, and MRI on Charcot joint. Methods Eight patients with 8 Charcot joints underwent X-ray, CT, and MR examinations. 6 of them had syringomyelia, 1 patient had injury of the spinal cord, and 1 case had diabetes. All 8 patients had sensory reduction or deficit in the sick extremities. Results There were two types of Charcot joint, hypertrophic and atrophic. Radiographic and CT features of hypertrophic joint (n=3) showed hyperostotic osteosclerosis and mammoth osteophytes in the sick bones, periarticular ossification,and articular disorganization. Radiographic and CT features of atrophic joint (n=5) showed extensive bone resorption (destruction), periarticular debris, and articular disorganization. Main MRI features of Charcot joint included hydrarthrosis within joint capsule, thickened, loose, and elongated joint capsule with para-joint, peri-diaphysis, and inter-muscular extension in a pseudopodia pattern. The irregular joint capsule wall was presented as mild hypointensity on T 1WI, slight hyper-intensity on T 2WI, and was markedly enhanced after Gd-DTPA was administrated, which was considered as a characteristic manifestation of the lesion. Soft tissue mass containing hypo-intense stripes on both T 1WI and T 2WI was commonly noted adjacent to the involved joint. Conclusion X-rays plain film is the first choice for the diagnosis of Charcot joint, and MRI is pretty useful in the diagnosis of Charcot joint.

Objective To analyze the X -ray, CT, and MR imaging findings in osteoid osteoma. Methods Forty-eight cases of osteoid osteoma proved by surgical pathology were collected, including 33 males and 15 females. Among the 48 cases, all patients had plane films, 32 were imaged with CT scanning, 10 with MR imaging, and 8 with all three techniques. The imaging findings of osteoid osteoma and the ability of X-ray, CT, and MRI in demonstrating the nidus and the surrounding reaction were analyzed. Results The imaging manifestations of osteoid osteoma revealed a circular or oval nidus with different bone sclerosis around the nidus. The diameters ranged from 0.4 cm to 1.7 cm, with the average of 9.7 cm. There were also soft tissue and bone morrow edema around the nidus or distinct effusion of joint on MR imaging in all 10 cases. Among 48 cases, only 37 cases showed nidus on plane film. All 32 cases with CT scanning showed nidus. The display ratios of nidus were 77% for X-ray and 100% for CT, respectively. 10 cases with MR imaging could be diagnosed correctly. But the nidus could be affirmed in only 8 cases, and the nidus was affirmed by comparing with plane film or CT in the other 2 cases. Conclusion Nidus is the key in diagnosing the osteoid osteoma correctly. Plane film is still an important checking method for osteoid osteoma. CT scan is the best method to demonstrate the nidus. MRI can demonstrate the soft tissue and bone morrow edema around the nidus sensitively, but probably lead to an incorrect diagnosis. Combining with X-ray or CT, MRI can make an accurate diagnosis.

ObjectiveTo study MRI features and pathologic basis of various periosteal changes in rabbit VX2 bone tumor and to evaluate the role of MRI in the change of periosteum in bone tumor. MethodsBone tumor models were induced by injection of VX2 carcinoma cell suspension into the medullary cavitv of right tibias in 32 rabbits.Thirty-six positive contrast cases and 4 negative contrast cases were established.Serial plain films and MRI examinations were performed at an interval of 5 days foliowing the implantation.Every 4 rabbits were sacrificed immediately after imaging. The findings of periosteal changes were compared between imaging features and pathologic Results . ResultsFrom the 5th to 15th day after implantation of VX2 carcinoma,periosteal edema was demonstrated in 32 tibias. On the 20th day,periosteal thickening Was revealed in 19 tibias. On the 25th day,periosteal new bone with the thickened periosteum attaching to its outer Surface was found in 12 tibias. On the 30th day,periosteal new bone with the thickened Deriosteum were elevated by the tumor in 11 tibias.On the 35th to 40th day,destruction of periosteal bone and periosteum were revealed.ConclusionsThe progress of periosteal changes in rabbit VX2 bone tumor included periosteal edema,periosteal thickening,periosteal new bone,destruction of periosteal new bone and destruction of periosteum. Various periosteal changes could be demonstrated on MRI and MRI is useful in evaluating periosteal changes.