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.

Objective To prospectively evaluate the diagnostic ability of the lesions′ morphology, signal intensity time course, and early phase enhancement rate in dynamic MRI of the breast. Methods Forty cases with breast lesions were examined with a new Efgre 3D dynamic MR imaging series. Time signal intensity curves of the lesions were obtained and classified according to their shapes as monophasic, biphasic, or washout. Early phase enhancement rates of the lesions were calculated. The diagnostic indices were got by lesions′ morphology criterion, the time signal intensity curves criterion, and the enhancement rate criterion. Results There were 23 malignant and 18 benign lesions. The distribution of curve types for malignant lesions was monophasic (5%), biphasic (18%), and washout (77%). The distribution of curve types for benign lesions was monophasic (72%), biphasic (11%), and washout (17%). The distribution proved significantly difference (? 2=20.68, P

Objective To investigate MRI examination methods and imaging manifestations of primary ureteral carcinoma, and to evaluate its clinical values when comparing with other diagnostic imaging facilities. Methods Eighty-seven cases of primary ureteral carcinoma who were operated within recent 8 years came into the study, among which, 35 cases had MRI examinations. For MRI examination, coronal heavy T2WI (water imaging) was performed to show the dilated ureter, then axial T2WI and T1WI were scanned at the obstruction level. 11 cases underwent additional Gd-DTPA dynamic contrast enhanced scans. The original pre-operative diagnostic reports of various imaging facilities were analyzed comparing with the results of operation and pathology. Results MRI showed ureteral dilatation in 33 of 35 cases, no abnormal appearance in 1 case, and only primary kidney atrophy post renal transplantation in 1 case. Among the 33 cases with ureteral obstruction, soft mass at the obstruction level was detected on axial scans in 32 cases. The lesions showed gradual and homogeneous mild to moderate enhancement on contrast MRI. The overall employment rate of imaging facilities was as follows: ultrasound (94. 3% ) , IVU (59. 8% ) , CT (52. 9% ) , MRI (40. 2% ) , and RUP (35. 6% ). The accurate diagnostic rate was as follows: MRI (91. 4% ) , RUP (80. 6% ) , CT (63. 0% ) , ultrasound (47. 6% ) , and IVU (11. 5% ). Conclusion Combination of MR water imaging and conventional sequences can demonstrate most primary ureteral carcinoma lesions and has a highest diagnostic accuracy among the current diagnostic imaging facilities. It should be taken as the first diagnostic imaging method of choice when primary ureteral carcinoma is suspected after ultrasound screening.

Objective To describe the characteristic MR findings in the brain in patients with amyotrophic lateral sclerosis (ALS), and to assess the diagnostic value of conventional MR imaging and fractional anisotropy (FA) of diffusion tensor imaging (DTI). Methods Conventional MR imaging was performed in 14 clinically proved ALS patients and 12 age-matched normal controls. Contrast enhanced MR images were acquired in 2 patients. Axial and coronal DTI scans were performed in 10 patients and 12 normal controls with SE-EPI sequence. The b value was 1 000 s/mm 2, the number of diffusion sensitive gradient direction was 25. For quantitative assessment of the corticospinal tract (CST), FA value of bilateral CST was measured at the level of posterior limb (PL) of the internal capsule (IC) and the cerebral peduncle of the midbrain, respectively, and statistical analysis was performed. Results Focal slight low signal intensity on T 1WI and high signal intensity (hyperintense to gray matter) on T 2WI was demonstrated in 6 ALS cases (42.9%) in bilateral PL of the IC, and the high signal was longitudinally continuous from the PL to the cerebral peduncle on T 2WI coronal plane, corresponding to the course of CST. In another 8 ALS cases (57.1%), the focal slight low signal intensity on T 1WI and slight high signal intensity (isointense to gray matter) on T 2WI was revealed in bilateral PL of the IC. No abnormal contrast enhancement was detected in the 2 cases. In control group, the focal slight low signal intensity on T 1WI and slight high signal intensity (isointense to gray matter) on T 2WI was demonstrated in all 12 subjects in bilateral PL of the IC. FA values of the patient group were significantly lower than that of the control group at the level of the PL of the IC (F=7.38, P

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.

Objective To investigate the MR manifestations and diagnostic value in patients with choroidal fissure cyst of the brain. Methods Characteristic MR findings in 16 patients with choroidal fissure cyst were retrospectively analyzed, and the correlation between MR imaging and clinical manifestations was reviewed. Results The cysts were situated within the choroidal fissure in all cases, representing as cystic lesion with clear border, no detectable soft tissue mass in the cyst wall or adjacent area, homogenous signal intensity identical to CSF on all sequences, with the average size of 0.9 cm?1.3 cm?1.5 cm, and no associated edema. Gd-DTPA was performed in 6 cases and revealed no evidence of enhancement. Conclusion The choroidal fissure cyst of the brain is a benign and congenital developmental abnormality, and has minor clinical significance. Because of its specific anatomic location, the choroidal fissure cysts simulate intraparenchymal cystic lesions on axial images. Coronal and sagittal MR imaging can be used to delineate its extraaxial location and make the correct diagnosis, and, thus, differentiate with other cystic lesions.

Purpose To explore the correlation between whole body magnetic resonance diffusion-weighted imaging (WB-DWI) quantitative parameters of healthy adults' bone marrow with gender, age, height, weight, body mass index, and sex hormone levels. Materials and Methods 108 healthy adult subjects in different age groups underwent WB-DWI scan using GE 1.5T MR scanner, among them estradiol and progesterone levels were measured in 60 subjects within 48 hours before or after the scan. Apparent diffusion coefficient (ADC) values of bone marrow and the signal to noise ratio (SNR) were compared among different gender and age groups. Partial correlation analysis was used to evaluate the correlation of skeletal system ADC values and SNR with sex, age, height, weight, body mass index, estradiol and progesterone levels in 60 subjects. Results ADC values and SNR of the female subjects were significantly higher than males (P<0.01);there were significantly differences for skeletal system ADC values and SNR in different age groups (P<0.01). Skeletal system ADC values was significantly negatively correlated (r=-0.642, P<0.01) with age, and were mildly positively correlated (r=0.278, 0.271, P<0.05) with estradiol and progesterone levels;SNR was significantly negatively correlated (r=-0.709, P<0.01) with age, and was mildly positively correlated (r=0.293, P<0.05) with estradiol levels;ADC values and SNR had no significant correlation with height, weight and body mass index. Conclusion Skeletal system ADC values are effected by gender, age and sex hormone levels, the skeletal system WB-DWI manifestations are different in different gender and age groups.

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

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.

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.