The value of DTI: achieving high diagnostic performance for brain metastasis.

BACKGROUND: The evaluation of brain metastases generally requires post-contrast MRI exam, but some patients have contraindication to contrast medium administration. PURPOSE: To investigate the value of the MRI diffusion tensor imaging (DTI) for detection of metastatic brain tumor. MATERIALS AND METHODS: We retrospectively analyzed the MRI data from 23 patients (13 males and 10 females) with brain metastases. The MRI protocol consisted in T1WI, T2WI, post-contrast 3DT1WI and DTI images (b = 1000) sequences. The brain metastatic lesions were counted in each of these sequences. We compared the advantages and limitations of different sequences in the brain metastases detection. The number of metastatic lesions identified on the contrast-enhanced 3DT1WI image is used as the reference. FA values were measured in the intratumoral, adjacent peritumoral and distant peritumoral edema area (PTEA) of brain metastasis, and the differences were statistically analyzed. RESULTS: DTI can detect more brain metastatic lesions rather than T1WI and T2WI. The number of brain metastases on DTI is similar to post-contrast 3D T1WI. There is no statistical difference in the FA value change between the adjacent and distant PTEA. CONCLUSION: The DTI original image can be used as an alternative examination for patients with contraindications to contrast-enhanced MRI. It has high sensitivity to intratumoral hemorrhage, which has advantage to detect brain metastatic lesions as compared with T1WI or T2WI images.

Study on hemodynamics of ventricular aneurysm with myocardial infarction by vector flow mapping / 中华超声影像学杂志

Objective:To observe the changes of left ventricular energy loss(EL) and apical wall shear stress(WSS) in patients with ventricular aneurysm by using vector flow mapping (VFM).Methods:Twenty-seven patients with ventricular aneurysm were selected as the case group, and they were divided into the ventricular aneurysm group(16 cases) and ventricular aneurysm thrombus group(11 cases) according to whether the apex of the heart was accompanied by thrombosis. Twenty healthy people were collected as the control group. Ventricular structure and cardiac function parameters were measured and the VFM offline analysis was performed. Systolic and diastolic phases were determined based on time-flow curve(T-F curve) and the open-close of valves, the corresponding left ventricular energy loss and the parameters of the WSS of the apex segment of the heart were obtainedand then compared between groups.Results:①In diastolic and systolic phases, EL values of left ventricular apical segment in ventricular aneurysm group and ventricular aneurysm thrombus group were lower than that in control group (all P<0.05). ②In diastolic phase, the peak WSS values of septal apical, lateral apical and anterior apical segments in ventricular aneurysm group and ventricular aneurysm thrombus group were lower than those in control group (all P<0.05), and the mean WSS of anterior apical segment in aneurysm group was lower than that in control group ( P<0.05). ③In systolic phase, the peak WSS values of anterior wall in ventricular aneurysm group and ventricular aneurysm thrombus group were lower than those in control group, and the mean WSS of anterior wall in ventricular aneurysm group was lower than that in control group (all P<0.05). The mean WSS of anterior wall in ventricular aneurysm thrombus group was higher than that in ventricular aneurysm group( P<0.05). Conclusions:VFM technology can quantitatively evaluate the EL and WSS of patients with left ventricular aneurysm, and provide a new perspective for further understanding of intracardiac hemodynamics in patients with left ventricular aneurysm with or without thrombus.

DTI evaluation of mild articular cartilage injury in patellofemoral joint: Comparison with arthroscopy / 中国医学影像技术

Objective To evaluate the value of DTI in mild articular cartilage injury in patellofemoral joint.Methods The DTI and arthroscopy data of 82 patients wih routine MRI diagnosed as mild articular cartilage injury were analyzed retrospectively.According to the results of arthroscopy,40 cases of mild articular cartilage injury with Outerbridge classification Ⅰ or Ⅱ were divided into experimental group,and 33 cases with normal patellofemoral articular cartilage were divided into control group.There were 8 articular cartilage injury patients with Outerbridge classification Ⅲ or Ⅳ in patello-femoral join were excluded.The DTI data were analyzed compared with arthroscopy.Results Arthroscopy detected 62 lesions of cartilage injury in experimental group.Totally 49 lesions (49/62,79.03 ％) were detected by ADC pseudocolor image and 51 lesions (51/62,82.25 ％) were detected by FA pseudocolor image.The DTI pseudocolor images of articular cartilage injury showed uneven levels.The red or pink levels can been observed.Compared with the control group,ADC value increased and FA value decreased significantly in experimental group (both P＜0.05).Conclusion DTI can clearly display and detect mild articular cartilage injury in patellofemoral joint,which provide valuable information for early cartilaginous injury.

Diagnostic value of water enema (18)F-fluorodexyglucose positron emission tomography and computed tomography in incidental finding of hypermetabolism focus in the colorectum / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the value of water enema (18)F-fluorodexyglucose positron emission tomography and computed tomography((18)F-FDG PET-CT) in incidental finding of hypermetabolism focus in the colon and rectum for differential diagnosis of benign or malignant lesions.</p><p><b>METHODS</b>From June 2010 to December 2012 in our hospital, 77 patients were found incidentally with uncertain hypermetabolism focuses in the colon and rectum during PET-CT examination. Water enema (18)F-FDG PET-CT was performed to classify the lesions. According to the pathological examination and clinical follow-up, these cases were divided into malignant disease (including advanced colorectal adenoma), benign adenoma, inflammation and physiological uptake. Radioactive uptake level (SUVmax) and change of water enema imaging (retention index, RI) of hypermetabolism focus were compared between groups.</p><p><b>RESULT</b>Of these 77 cases, 23 were malignant diseases, 16 benign adenoma, 7 inflammation and 31 physiological uptake. The difference of average SUVmax was not statistically significant between benign and malignant lesions as well as physiological uptake(P>0.05). But the difference of RI was statistically significant between neoplastic lesions and inflammation(P<0.05). The accuracy of water enema (18)F-FDG PET-CT in diagnosing non-neoplastic uptake was 100%, and the sensitivity, specificity and accuracy in differentiation of malignancy form benign lesions were 95.6%, 96.3%, and 96.1% respectively.</p><p><b>CONCLUSIONS</b>The incidental focal colorectal (18)F-FDG uptake in PET-CT may indicate potential colorectal malignant lesions and adenoma. Water enema can effectively differentiate the physiological uptake and predict benign lesions or malignancy in the colon and rectum colorectum with good accuracy.</p>

MR imaging of short T2 components with three dimension ultrashort echo time double echo pulse sequence:investigation of factors affecting imaging quality / 中华放射学杂志

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.

Parameters optimization of diffusion tensor MR imaging of the human calf at 3 tesla / 中华放射学杂志

Objective To demonstrate the feasibility of DTI in human calf with body phased-array coil and surface coil of spine as receiving coil on 3 T system, and to optimize the parameters of sequence, including slice thickness and b-value. Methods Fifteen healthy volunteers were recruited in this study and randomly divided into three groups. The DTI sequence for head was performed on calf in the first group (5 cases), and the sequence parameters were optimized based on the deficits of the raw and the post-processed DTI images. Then, different slice thickness were applied in the senond group (5 eases) to optimize the slice thickness, and this optimized parameter with the highest score based on quality of the post-processed DTI images was applied in the next step. Finally, different b values were applied in the last group to optimize this parameters. The b value with the highest score based on the quality of the pest-processed was the proper one. Results Three problems existed in the raw and the pest-processed images, when the DTI sequence for brain was used for the calf. First, the SNR of raw images is extremely low. Second, the muscle were unclear on the image with parts of signal lose, especially in the anterior tibialis muscle. Finally, the artifacts due to chemical shift and ghost are quite serious. The scores for muscle display quality with slice thickness of 4 mm , 5 mm and 6 mm were (7.0±0. 0), (8.6±0. 9) and (9.0±0. 0) score respectively, the signal less scores were (5.0±0. 0) and ( 12. 8±2. 6) and ( 13. 8±2. 2) score respectively, and the general score were (22. 0±0. 0) and (30. 1±3.8) and (31.0±4. 1 ) score respectively. The differences of above scores were significant among different slice thickness (F-value were 21. 000 and 30. 544 and 12. 390 respectively, P <0. 05 ). The muscle displaying quality, signal loss and general scores were lowest in group with 4 mm slice thickness (q-value were 4. 896.6. 120,6. 327,7. 138,3. 863 and 4. 043, P < 0. 05 ) o The scores of muscle display quality, signal loss and general for b =400 s/mm2 were (9. 0±0. 0), ( 14. 0± 2. 2 ) and ( 33.0±2. 2 ) score respectively, which were lower than those with b = 800 s/ram2 [(7.0±0.0), (6.2±2.2), (21.8±3.4) score] and b=1000 s/mm2[(7.0±0.0), (5.0±0.0), (20.6±2.2) score] (q-value were 3.873,3.873,6.650,7.672,7. 101 and 5.917, P <0.05)o The scores of muscle displaying quality, signal loss and general for b =600 s/mm2 were (8.2±1.1 ), ( 13.0± 2. 3) and ( 30. 8±3. 8 ) score respectively, which were higher than those with b = 800 s/mm2 and b= 1000 s/nun2 (q-value were 3.873, 3.873, 5.797, 6.820, 5.326 and 5.917, P <0.05).There is no significant difference between b = 600 s/ram2 and 400 s/ram2 ( q-value were 2. 582 and 0. 852 and 1. 775, P > 0. 05 ). Conclusion Our preliminary findings indicate that it is feasible to perform DTI on human calf with 3 T MR. With body phased-array coil and surface coil of spine as receiving coil, the DTI sequence were optimized to acquire enough SNB with slice thickness of 5 mm and b-value of 400 s/mm2.

The preliminary application of the 3D ultrashort TE double echo pulse sequence in the bone and joint MR imaging / 中华放射学杂志

Objective To investigate the application of 3D ultrashort TE double echo pulse sequence in the bone and joint MR imaging. Methods Eight volunteers and a porcine fibula in vitro with intact muscle were involved in this study. Among the volunteers, one was suspected with meniscus tear, the others were asypmtomatic. MR imaging of 3D ultrashort TE double echo pulse sequence were performed on the tibial diaphysis, knee joint, ankle and wrist of each volunteer and the porcine fibula in vitro. Using the first echo images subtract with the second echo images, we observed the subtracted images from the primary double echo images and MPR images respectively. We then compared the difference of SNR. Four different echo times of the first echo (TE1) in the images were set as 0. 08 ms, 0. 16 ms, 0. 24 ms, 0. 35 ms. The quality of the subtracted images from the primary double echo images of the four different TE1 was compared.The MIP images from the primary double echo images with TE1 of 0. 08ms were performed to display the 3D structure of the ankle tendons. The data were analysed with One-Way ANOVA and Paired-Samples t test statistically. Results The 3D images of the tendons were displayed through MIP of the subtracted images from the primary double echo images. The cortical bones, periosteums, tendons and menisci of the 8 volunteers appeared as high signal intensity in UTE pulse sequence. The SNR of the subtracted images from MPR images (SNR, 3.76 ± 0. 88) was significantly higher than those from the primary double echo images(SNR,2. 82±0. 75) (t = - 4. 851, P < 0. 01). There were significant differences among the subtracted images from each of the four different TE1. The highest quality were obtained from the TE1 of 0.08ms. The CNR were as follows: CNR<,0.08ms>1.74±0. 54, CNR<,0.16ms> 1.35 + 0. 60, CNR0.24ms>1.20±0. 48,CNR<0.35ms> 0.89±0. 24 (F = 3. 681, P < 0. 05). The artifacts appeared markedly with prolonging of the TE1.Conclusion The MRI of ultrashort TE double pulse sequence may display the short T2 components that appeared as low signal with conventional clinical MR imaging, which made it pessible to quantify the tissues containing a majority of short T2 components.