A finger-taping switch task functional magnetic resonances imaging study in the patients with Tourette's syndrome / 中华神经科杂志

ObjectiveTo investigate the central nervous system mechanisms of active of movement switch in the patients with Tourette' s syndrome( TS),and to explore the possible underlying distinct neural networks for tic trigger and generation. Methods Participants were 14 patients with TS and 14 age- and gender-matched healthy volunteers with no history of physical,psychiatric or neurological disease: All patients were assessed with functional magnetic resonances imaging (fMRI)of the brain during the intermittent performance of finger-tapping switch tasks,Blood-oxygen-level dependent-fMRI was performed using a 3.0 Tesla MR.The area over which the activation was distributed was calculated,and the activation volumes were also compared between the patients with TS and the control subjects.ResultsThe regions activated in the patients with TS and in the volunteers were similar in several brain regions,including contralateral precentral and postcentral gyrus,contralateral mesia pre-front gyrus,contralateral cingulate gyrus,contralateral insula and ipsilataral cerebellum. There were also many different activation areas between the patients and the control subjects. The patients with TS demonstrated more significant and extended activation in the contralateral pre- and postcentral gyrus than the healthy volunteers.The volume of the left pre- and postcentral gyrus of the TS patients was (8.024 ±0.071 ) cm3,while the volume of the left pre-and postcentral gyrus of the control subjects was ( 6.480 ± 0.026) cm3 ( t =3.026,P ＜ 0.01 ) ; The volume of the right pre- and postcentral gyrus was (6.192 ± 0.019) cm3 in the TS cases,while there was (5.608 ±0.037) cm3 in the control subjects (t =2.752,P ＜0.05).There were significant differences in the volumes of bilateral pre- and postcetral gyrus between the TS and control subjects. The activations of conralateral thalamus without contralateral insula were found in the patients with TS. Conversely, the contralateral insula activation without thalamus activation could be found in the healthy volunteers.ConclusionThe thalamus might play an important role in the aetiological and physiopathologic mechanisms of the TS. The thalamus along with the parietal cortex,cingulate cortex and insular cortex appear to constitute a distinct neural network for tic trigger and generation.

H-magnetic resonance spectrum of putaman of Tourette' s syndrome / 中华神经科杂志

Objective To study the changes of the putamen metabolites with magnetic resonance spectrum(MRS),and to explore possible underlying unrecongnised aetiological factor and pathophysiology mechanism in the central nervous system of the patients with Tourette' s syndrome.Methods Twenty-two cases of Tourette' s syndrome,and twenty-two gender and age-matched subjects ( the control subjects ) were performed on a clinical 3.0 T MRI system.Proton prob-voxel spectroscopy imaging (1H-MRS) was obtained from two sides of the putamen.The metabolites included N-acetylaspartate (NAA),creatine and phosphocreatine ( Cr),choline-containing compounds (Cho),and myoinositol ( MI ).The value of the NAA,Cr,Cho,and MI were calculated by integration of their peaks.The ratios of NAA/Cr,Cho/Cr,ML/Cr were calculated respectively.Repeated measures analysis of variance ( ANOVA ) was used to test both the value of NAA/Cr,Cho/Cr,MI/Cr of the putamen for group difference,with group as between-subjects factor and side as within-subjects factor.Results The NAA/Cr ratio in patients ( left:1.29 ± 0.13 ; right:1.34 + 0.15 ) was significantly lower than that in the control subjects ( left:1.50 ± 0.08,T =1.962,P ＜0.05 ; right:1.52 ± 0.11,T =1.865,P ＜ 0.05 ).There was no significant difference in the Cho/Cr and MI/Cr ratio between both groups.Conclusion The abnormalities of the structure and(or) function in the putamens of patients may be the one of the underlying anaetiological factors and pathophysiology mechanisms of the Tourette' s syndrome.

High resolution MR imaging of porcine coronary arterial wall in vitro / 中国医学影像技术

Objective To get a MR imaging protocol for coronary arterial wall in vitro. Methods MR examinations were performed in 10 fresh porcine hearts. Three dimensional fast imaging employing steady state acquisition (3D FIESTA) was used to delineate left anterior descending artery (LAD), while 2D spin-echo T1W was performed with 8-channel head surface coil, temporomandibular surface coil and knee coil with the same parameters. T1WI was obtained with 384×256 and 512×512 in matrix using temporomandibular surface coil, and then T1WI, PDW and T2WI with fat saturation were obtained with different NEX using temporomandibular surface coil after injecting Resovist in LAD. Signal of the LAD wall, lumen, fat tissue adjacent to LAD, myocardium of anterior part of interventricular septum and noise were respectively measured. Signal-to-noise ratio (SNR) of image, contrast to noise ratio (CNR) between the wall and lumen (CNR1), CNR between the wall and surrounding fatty tissue (CNR2) were calculated. Results The SNR and CNR1, CNR2 of SE T1WI with temporomandibular coil were higher than those with 8-channel head surface coil and knee coil. SNR and CNR1, CNR2 of SE T1WI with 384×256 matrix were higher than those with 512×512 matrix. SNR and CNR1, CNR2 using 3 NEX were the highest. Conclusion Good SNR and CNR of porcine coronary wall can be achieved using temporomandibular surface coil, 384×256 in matrix and NEX of 3.

Quick injection combining with slow infusion of contrast media on coronary MR angiography / 中华放射学杂志

Objective To evaluate the effect of quick injection combining with slow infusion of Gd-DTPA on T1 relaxation of the blood. Methods Fifteen volunteers were recruited for coronary MRA study using a navigator-gated 3D-FIESTA sequence. Coronary MRA were acquired on the same segments two times at 5 minutes and 15 minutes after Gd-DTPA administration. Contrast agent was injected biphasically with 10 ml at a flow rate of 1.5 ml/s and 20 ml at 0. 05 ml/s to prolong the T1 relaxation effect. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated pre- and post-contrast MRA. Image quality was compared using t-test. Results The SNR and CNR at 5 minutes after contrast injection (35.37 ±6. 84 and 21.57 ± 6. 08 ) were significantly higher than that of pre-contrast MRA ( 27.38 ± 6. 24 and 13.19 ±6. 50). The SNR at 15 minutes after contrast injection (33. 81 ±9. 43) was higher than that of precontrast MRA, but there was no statistically difference(t = 1. 885 ,P =0. 074). The CNR at 15 minutes after contrast injection (21.20 ± 7.65) was significantly higher than that of pre-contrast MRA. The SNR and CNR at 15 minutes after contrast injection were no significant different compared with those at 5 minutes after contrast injection. Conclusion T1-shorting effect in the blood can be prolonged by quick injection combining with slow infusion of Gd-DTPA ,which meet with the need of multiple scans of coronary MRA.

Corticospinal tract degeneration in amyotrophic lateral sclerosis: a diffusion tensor imaging and fibre tractography study

<p><b>INTRODUCTION</b>Motor neuron damage and cortical spinal tract (CST) degeneration in amyotrophic lateral sclerosis (ALS) are difficult to visualise and quantify on conventional magnetic resonance imaging (MRI).</p><p><b>CLINICAL PICTURE</b>We studied 8 ALS patients and 12 normal volunteers using diffusion tensor imaging (DTI) and fibre tractography using fibre assignment by continuous tracking (FACT) to study the fibres of the CST and the posterior thalamic radiation (PTR), a nonmotor tract.</p><p><b>OUTCOME</b>Fibre tractography was successfully performed in all normal volunteers and all patients except 1. The fibre bundles of the CST, but not the PTR, were significantly reduced (P <0.05) in patients compared to normal volunteers.</p><p><b>CONCLUSION</b>Fibre tractography can visualise axonal degeneration in the CST and may provide supplementary information about upper motor neuron disease in ALS patients.</p>

Comparison of 16 slice multi-detector computed tomography and breath hold 3D magnetic resonance angiography in the detection of coronary stenosis / 老年心脏病学杂志（英文版）

Objective To compare 16-slice multi-detector spiral computed tomography (MDCT) and breathhold 3D magnetic resonance (MR) coronary angiography in the visualization of coronary arteries and the accuracy of detecting significant (＞ 50%) coronary stenoses in patients with suspected coronary artery disease. Methods Forty patients were examined by 16-slice CT (GE, Lightspeedl6)and MR (GE,Twinspeed) within 3 days; 31 of them underwent conventional coronary angiography (CAG) within 2 weeks after CT and MR scan. CT was performed with 16× 1.25 mm detector collimation, 0.5 s rotation time and images were reconstructed at 60%-75% of the cardiac cycle. MR was performed with breath hold 3D FIESTA (TR4.0 ms, TE1.7 ms, flip angle 65, slice thickness 3 mm, FOV 280 mm, matrix 256× 192). Mean heart rate was 63 ± 5.8 bpm and β-blocker was used in 24 patients. MR and CT image quality was evaluated in 9 coronary segments (RCA1, RCA2, RCA3, LM, LAD1, LAD2, LAD3, LCX1, LCX2) using a four-point grading scale.Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated for detection of significant stenosis using CAG as the gold standard. Results 16-slice CT showed higher image quality in most coronary segments except RCA2.Forty-three segments were diagnosed as significant stenosis by CAG, 36 and 27 of these were correctly detected by CT and MR respectively. Sensitivity, specificity, positive predictive value, and negative predictive value of 16-slice CT and MR for detecting significant stenosis were 83 %, 84 %, 49 %, 97 % and 63 %, 90 %, 55 %, 93 %, respectively. Conclusion Sixteen-slice CT showed higher image quality in most coronary segments excepted for middle RCA. 16-slice CT had higher sensitivity than MR for detection of coronary significant stenosis, whereas MR had higher specificity than CT. Both CT and MR showed high negative predictive value,which is useful for excluding coronary stenosis in symptomatic patients.

Evaluation of reperfusion injury and left ventricular remodeling after acute myocardial infarction with MRI / 中国组织工程研究

BACKGROUND: The MRJ studies of acute myocardial infarction (AMI)were more frequently focused on the changes of myocardial perfusion. OBJECTIVE: To investigate the characteristics of infarction and myocardial reperfusion in MRI, and make comparison of them with the results of their staining pathologic sections. DESIGN: Completely randomized grouping design and randomized controlled study. SETTING: Magnetic Resonance Department of Air-force General Hospital of Chinese PLA and Radiological Department of General Hospital of Chinese PLA. MATERIALS: The experiment was completed in the Medical Animal Experimental Center, General Hospital of Chinese PLA in December 2003.Fourteen miniature pigs were divided into 2 groups: infarction group and reperfusion group with 7 pigs in each group. One-month before and after the operation, MRI was performed in order to strengthen the scanning examination. One-month after operation, axial plane pathologic slices, which were corresponding to the MRI, were given TTC and SE staining. According to the TTC staining results, samples of the infarcted myocardium (corresponding to the anterior wall of the left ventricular) and normal myocardium (corresponding to the posterior wall of the left ventricular) were taken and given HE staining to observe the extent of infracted myocardium. MAIN OUTCOME MEASURES: The changes in cardiac shape and function and the changes of myocardial T1 and T2 relaxation time. RESULTS: Fourteen Chinese miniature pigs were used with 7 in each group. ①Relaxation time of T1 and T2 of infarcted myocardium in infarction group was obviously longer than that of thenormal myocardium [1 159.54±78.67, (60.15±6.31) ms, 1 056.15±70.95, (47.46±7.94) ms, t=2.63,5.38, P＜ 0.05, 0.01] and that of the infarcted myocardium in reperfusion group was also obviously longer than that of normal myocardium [1 171.14±139.98,(56.64±6.16) ms, 1 074.64±97.61, (44.57±4.25) ms, t=2.64, 6.24, P ＜ 0.05,0.01].②MRI in single infracted myocardium and reperfused infracted myocardium was both changed obviously,but without significant differences in relaxation time and stress.Dilatation of left ventricle in single infracted group was more obviously than that in the reperfusion infracted group.③Theresult of MRI was coincidence with that examinated with TTC staining CONCLUSION:①MRI is a useful imaging modality in the evaluation of AMI and the left ventricle remodeling after myocardial infarction.②It is significant for reperfusion to treat remodeling of left ventricle after acute myocardium infarction.③There is good correlation between MRI and pathological examination.

~1H MR spectroscopy of C6 glioma after tumor necrosis factor-?therapy / 中华放射学杂志

Objective To observe the therapeutic effect of tumor necrosis factor ?(TNF ?) on C6 glioma using 1?H MR spectroscopy, and to evaluate the practical value of 1?H MR spectroscopy in observing therapeutic effect Methods C6 cell mixed with low boiling point argarous were inoculated in caudate nuclear in 33 rats by using sterotatic method By using high magnetic field spectrometer, high resolution 1?H MR spectroscopy was carried at a 3 day interval until 15 days after treatment with TNF ? The relative choline containing compound (Cho),N acetyl aspartate (NAA),creatine (Cr), Cho/Cr,NAA /Cr,and NAA/Cho were analyzed with statistic method Results The Cho decreased obviously 3 days after TNF ? treatment( P

MRI of demyelinating pseudotumor of the central nervous system / 中华放射学杂志

Objective To describe the MR manifestations of demyelinating pseudotumor of the central nervous system (CNS), and to discuss the pathologic features and MR diagnostic value and limit in this disease entity. Methods Seven pathologically proved and one clinically proved cases of demyelinating pseudotumor of CNS were studied with MR imaging, and the MR imaging features were retrospectively analyzed. Results MR imaging demonstrated localized mass without adjacent multiple accompanying lesions in all 8 cases. On T 1WI, the lesions showed homogenous low signal in 5 cases, inhomogenous low signal in 2 cases, and mixed high and low signal in 1 case. On T 2WI, the lesions presented as homogenous high signal in 5 cases and inhomogenous high signal in 3 cases. Of the 7 cases with Gd DTPA administration, marked enhancement was seen in each case. The enhancement pattern of vertical distribution to the lateral ventricle was demonstrated in left frontoparietal lobe in one case, and predominant dorsal white matter enhancement of the cervical spinal cord was revealed in another case. Follow up MR imaging showed no lesion recurrence, and gradual shrinkage of the lesion after steroid therapy was demonstrated in one case. Conclusion It is a difficult task to make the correct diagnosis of CNS demyelinating pseudotumor based on the clinical information and imaging findings, and this disease entity is often misdiagnosed as tumor by MR imaging. Thorough analysis of the clinical history and careful observation of MR manifestations (especially contrast enhanced MR findings) would be helpful in diagnosing the demyelinating pseudotumor and, in such circumstances, providing test steroid therapy, thus avoiding the devastating injury caused by surgery or radiation therapy.

Hepatic adenomas: comprehensive imaging diagnosis / 中华放射学杂志

Objective To describe the US, CT, and MR imaging findings and diagnosis of hepatic adenomas. Methods The comprehensive imaging features in 6 patients with 6 hepatic adenomas confirmed pathologically were reviewed retrospectively and correlated with pathologic findings. Results One case was diagnosed correctly, four cases were mistaken for hepatocellular carcinomas (HCC), and one case was mistaken for focal nodular hyperplasia. US: six lesions were hypoechoic with hypohalo in four lesions, and there was low velocity arterial and venous flow within the six lesions. CT: six lesions were hypodense with pseudocapsule in four lesions, and the four lesions showed slight enhancement during arterial and portal venous phases, and one lesion showed moderate enhancement during arterial phase and slight enhancement during portal venous phase. MRI: six lesions had heterogeneously high signal intensity on T 1WI and T 2WI, and the high intensity on T 1WI remained unchanged after using fat saturation. Two lesions showed strong enhancement during arterial phase and slight enhancement during portal venous and delayed phases, and three lesions showed slight enhancement during arterial, portal venous, and delayed phases. Pseudocapsule detected in six lesions showed slight enhancement on portal venous or delayed phases. Conclusion The comprehensive imaging findings of hepatic adenomas were nonspecific. The presence of pseudocapsule, heterogeneous high signal intensity on T 1WI, and the high intensity remained unchanged after using fat saturation may help make a correct diagnosis of hepatic adenoma.

Hepatic angiomyolipoma: correlation of MRI and pathologic findings / 中华放射学杂志

Objective To describe the MR imaging features and pathologic findings of hepatic angiomyolipoma (HAML), and to evaluate the utility of MR imaging in diagnosis of this tumor. Methods The MR imaging features of eight patients with HAMLs confirmed pathologically were analyzed retrospectively and correlated with pathologic findings. Results Eight patients had a solitary hepatic mass, five (mixed type HAML) of which were diagnosed correctly, and two (1 myomatous type HAML and 1 angiomatous type HAML) of which were diagnosed as hepatic adenoma and focal nodular hyperplasia, and one (mixed type HAML) with hemorrhage and multiple cystic change was mistaken for malignant tumor. Six cases of mixed type HAML exhibited heterogeneously high signal intensity on T 1 and T 2WI. The high signal intensity on T 1WI in five cases disappeared completely after using fat saturation, and most part of the high signal intensity in one case disappeared and some of the high signal intensity remained unchanged after using fat saturation, and multiple cystic change within this mass was detected. One myomatous type HAML and one angiomatous type HAML showed hypointensity on T 1WI and hyperintensity on T 2WI. Multiphase dynamic Gd DTPA enhanced MR scanning was performed in six patients and all those masses showed strong enhancement during arterial phase, and four of which showed moderate enhancement and two slight enhancement during portal venous and delayed phase. Pseudocapsule detected in five cases showed slight enhancement on portal venous and (or) delayed phase. Conclusion MR imaging can reveal the characteristic findings of mixed type HAML and accurate preoperative diagnosis can be made.

MR angiography of internal carotid artery stenosis: contrast enhanced MRA versus gated 2D TOF MRA / 中华放射学杂志

Objective To compare the accuracy of CE MRA and Gated 2D TOF MRA in evaluation of internal carotid artery stenosis. Methods 34 patients (male 27, female 7, age range 45-78 years) were evaluated with contrast enhanced three dimensional magnetic resonance angiography (CE MRA) and unenhanced ECG gated two dimensional time of flight MRA (Gated 2D TOF MRA). Digital subtraction angiography (DSA) was used as the “gold standard”. The MRA images were reprojected with maximum intensity projection (MIP) algorithm. Sensitivity, specificity, diagnositic accuracy,overestimation and underestimation were assessed. Results (1) DSA provided 68 diagnostic judgments: 23 were negatives and 45 were positives (mild stenosis 10, moderate stenosis 14, severe stenosis 17, occlusion 4). CE MRA was in agreement with angiography in 66 (97%), but overestimation resulted in 2 cases. Gated 2D TOF MRA was in agreement with angiography in 56 (82%), with 9 overestimation and 3 underestimation. (2) Taking negative and positive cases as judgement, CE MRA showed higher sensitivity, specificity, and diagnostic accuracy than Gated 2D TOF MRA (100% versus 95 6%, 100% versus 78.3%, 100% versus 89.4%, respectively). (3) Taking 70% stenosis as judgement, CE MRA also showed higher sensitivity, specificity, and diagnostic accuracy than Gated 2D TOF MRA (100% versus 95 2%, 97.8% versus 93.6%, 98.5% versus 94.1%, respectively). Gated 2D TOF MRA vs DSA, CE MRA vs DSA and Gated 2D TOF MRA vs CE MRA all had no significant difference (? 2=3.000 with P =0.083, ? 2=2.000 with P =0.157, and ? 2=1.600 with P =0.206 respectively) Conclusion Compared with Gated 2D TOF MRA,CE MRA is more accurate in evaluation of carotid artery stenosis.

Application of Magnetic Resonance Spectroscopy in Diagnosis of Intracranial Lesions / 实用放射学杂志

Objective To evaluate the clinical value of MR spectroscopy in intracranial neoplasm. Methods 52 cases with brain neoplasm or recurrent neoplasm or non-tumor lesion confirmed by pathology were undergone proton MRS before stereotactic biopsy, or operation. Results Of 52 cases, 38 were neoplasm and 14 were nonneoplastic lesion, 34 of 38 brain tumor, 11 of 14 nonneoplastic lesion were diagnosed correctly. The characteristics on MRS of glioma were remarkable Cho increase and NAA decrease, Lac in the tumors and the central necrotic area was elevated. Metastasis: Cho increased,NAA disappeared or obviously decreased and Lac increased, but the peritumoral region was normal. Lymphoma: Cho increased, NAA decreased moderately, Lip presented, but the peritumoral region was normal. Demyelination lesion: slight or median decreased NAA and normal Cr, Lac increased slightly. All metabolism decreased or disappeared in radiation necrosis, Cho was relative high compared with NAA. Brain abscess: Lac increased in the centre of abscess and perilesion was normal.Conclusion MRS has significant value in detecting and differentiating brain lesions.

Efficiency of breath-hold three-dimensional fast imaging employing steady state acquisition sequence for coronary stenoses detection / 中华放射学杂志

Objective To evaluate the efficiency of coronary magnetic resonance angiography (CMRA) for stenoses detection by using breath-hold three-dimensional fast imaging employing steady state acquisition (FIESTA) sequence with the reference of conventional coronary catheter angiography. Methods~Consecutive 33 patients accepted CMRA examination within 3 weeks after the catheter angiography. Coronary stenoses was graded in 5 levels as 0%, 0%-25%, 25%-50%, 50%-75%, and 75%-100%, respectively, and CMRA and catheter angiogram were compared segment by segment. Results For the differentiation of the stenoses 50%, the accuracy, sensitivity, and specificity of CMRA was 84.3%, 84.8%, and 84.1%, respectively, and the negative prediction value was 92.3%. The accuracy, sensitivity, and specificity for the differentiation of stenoses between 50%-75% and 75%-100% were all 61.5%. Conclusion The breath-holding three-dimensional FIESTA sequence for CMRA was practical to exclude hemodynamic significant coronary stenoses but limited in detail grading.

High resolution MR imaging in measurement of vascular wall area in atherosclerotic carotid artery: assessment of reproducibility / 第二军医大学学报

Objective: To assess the reproducibility of high resolution MR imaging(MRI) in measuring the vascular wall area in atherosclerotic carotid artery. Methods: Twenty four subjects (male 18, female 6, aged 60 78 years) with 50% 79% stenosis (confirmed by Doppler ultrasound) were recruited for the study. Two independent MRI examination were conducted within 2 weeks using high resolution imaging on a 1.5 T scanner (Signa, GE Medical Systems). Three slices were selected (4 mm distal to the bifurcation, just under the bifurcation and 4 mm proximal to the bifurcation) from the bilateral carotid artery to measure the luminal, outer wall boundary and wall area. The above process was done by 2 observers blinded to each other's results. The Interscan and Interobserver variations were assessed by paired Student's t test. Results: There was no significant difference in lumen, outer wall boundary and wall area measurement for both Interscan and Interobserver comparison. Conclusion: High resolution MRI of the human carotid artery in measuring the vessel lumen and wall areas has high reproducibility. MRI can also be used to monitor the progression of atherosclerotic plaque of carotid artery.

Localization strategy for magnetic resonance coronary angiography / 中华放射学杂志

Objective To develop a localization strategy for magnetic resonance coronary angiography (MRCA). Methods In 89 subjects, the standard 4-chamber view and long-axis view of left and right ventricle were acquired using Fast-Imaging-Employing-Steady-State-Acquisition (FIESTA) sequence in CINE mode, and the trigger-delay time for mid-diastolic phase was determined. Coronary vessels including right coronary artery (RCA), left main (LM), left anterior descending (LAD), and left circumflex (LCX) were localized and imaged using 3-dimensional fat-suppressed FIESTA sequence during end-expiration. The reproducibility of the localization strategy was evaluated by taking the standard of coronary segmentation system recommended by American Heart Association. Results Eighty-six subjects completed the examination with full respiratory co-operation and the indication ratio was 96.63%. Nine planes were optimized as the standard to target the main branches of coronary arteries, and a comprehensive reproducibility reached 100% in demonstrating the proximal and middle segment of RCA (AHA-18, 19), LM (AHA-1, 2), proximal and middle segment of LAD (AHA-3, 5, 7), and proximal LCX (AHA-10). The reproducibility for the demonstration of distal segments of LAD, LCX, and RCA (AHA-9, 14, 21) was 94.19%, 72.09%, and 96.51%, respectively. Conclusion This is a simple and practical localization strategy for MRCA. It could image the proximal and middle segments of the coronary arteries with good reproducibility, which indicates the potential for clinical application.

Imaging features of primary mediastinal cysts with clinical and histopathologic correlation / 中华放射学杂志

Objective To characterize the imaging features of mediastinal cysts and gain a better understanding of atypical manifestations of various mediastinal cysts and improve the level of diagnosis. Methods The CT and/or MR images(CT n=28, MRI n=26, CT and MRI n=10), surgical information, and pathologic material in 44 histopathologically proved cases of mediastinal cyst were retrospectively reviewed. Results The mediastinal cysts were located in the anterior mediastinum(n=13), middle mediastinum(n=18), anterior-middle mediastinum (n=2) and posterior mediastinum(n=11). Bronchogenic cysts and pericardial cysts were atypically located in 7/20(35%)and 5/6 respectively. The density of 42.9% cysts on CT was close to that of water. Each of the cysts had a high signal intensity that was equal to or greater than cerebrospinal fluid on T_2-weighted MR images. One cyst showed marked loss of signal on MR hydrography. The signal intensities of the cysts were variable on T_1-weighted images. The signal intensity of MRI was not homogeneous in 5 and the reasons were different. Fourteen cases were misdiagnosed. Conclusion 1.The cysts with soft-tissue attenuation on CT in the anterior and posterior mediastinum may be easily misdiagnosed as neoplasm. Pericardial cysts located in the paratrachea may be easily misdiagnosed as bronchogenic cysts .2. MRI can be used to diagnose the cysts with high density on CT.3. Heterogeneous signal on MRI and loss of signal on MR hydrography might be the reasons for misdiagnosis.

Comparative study of multi-detector CT and breathhold 3D MR coronary angiography in patients with coronary artery disease / 中华放射学杂志

50%) in patients with suspected coronary artery disease.Methods Both coronary MDCT angiography (CTA) and MR angiography (MRA) was performed within 3 days in 40 patients with suspected coronary artery disease, and conventional coronary angiography (CAG) was performed within 2 weeks after MDCT and MR scan in 31 patients. CTA was performed with a 16-MDCT scanner. MRA was performed on a 1.5 T MR scanner with breathhold 3D fast imaging employing steady state acquisition sequence. CTA and MRA image quality was evaluated in 9 coronarysegments by two experienced radiologists in concensus using a four-point grading scale. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for detection of significant stenosis on a segmental basis using CAG as reference and gold standard. Results MDCT showed higher image quality in most coronary segments except middle RCA (P