OBJECTIVETo reduce the acquisition time of carotid high-resolution contrast-enhanced magnetic resonance imaging (CEMRI), we designed a small field-of-view (FOV) quadruple-inversion-recovery (SF-QIR) T1WI and evaluated the image quality.

METHODSTwenty-four subjects with carotid plaque were enrolled in our study. All the subjects were imaged using the same 3.0T MRI by SF-QIR and standard rectangular FOV QIR (SrF-QIR) with identical parameters except for the phase-encoding step numbers and the RF excitation methods. Three independent readers qualitatively evaluated the differences between the two sequences in regard of the carotid outer wall border delineation, fibrous cap and lipid-rich necrotic core (LR-NC) border delineation, and diagnostic confidence. The quantitative measurements included maximal stenosis, wall area, LR-NC area, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). The inter-reader variability was assessed.

RESULTSThe application of SF-QIR combined with orthogonal radio frequency excitation resulted in nearly half of the scan time with the SrF-QIR. Both qualitative and quantitative assessment by the readers revealed no significant differences between the two sequences except for SNR and CNR (Pgt;0.05). Since the mean loss of SNR with SF-QIR was 37.7%, SrF-QIR demonstrated a superior performance in SNR (P<0.001).

CONCLUSIONThe small FOV QIR sequence is effective in high-resolution CEMRI for evaluating carotid plaques and can effectively reduce the scan time and eliminate motion artifacts.

Adult ; Aged ; Aged, 80 and over ; Carotid Artery Diseases ; diagnosis ; pathology ; Female ; Humans ; Image Enhancement ; methods ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged

OBJECTIVETo assess the value of high-resolution three-dimensional black-blood magnetic resonance imaging (3D-BB-MRI) in quantitative measurement of carotid atherosclerotic plaque by comparison with two-dimensional black-blood magnetic resonance imaging (2D-BB-MRI).

METHODSForty patients were scanned with routine 2D and oblique-sagittal 3D-BB-MRI. The original oblique-sagittal 3D images were reformatted to an axial 2D-like dataset. Two experienced radiologists identified the interested slice in consensus for every patient (unilateral carotid artery) in 2D-BB-MRI images and matched the axial reformatted 3D images with 2D black-blood images. Plaque thickness (PT), lumen area (LA) and total vessel area (TVA) were measured, and lumen stenosis (LS) and normalized wall index (NWI) were calculated.

RESULTSThere was no measurement difference between 2D-BB-MRI and reformatted 3D-BB-MRI (P>0.05), and these two methods had a good correlation (r<0.9). The Bland-Altman chart showed that 2D-BB-MRI and 3D-BB-MRI were in good agreement in the measurement of PT, LA and TVA.

CONCLUSION3D-BB-MRI and 2D-BB-MRI have no obvious difference in quantitative measurement of the carotid plaques. 3D-BB-MRI can demonstrate the vessels and plaques by multiplanar reconstruction and thus have better performance in evaluating carotid atherosclerosis compared with 2D-BB-MRI.

Adult ; Aged ; Aged, 80 and over ; Carotid Artery Diseases ; pathology ; Female ; Humans ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged

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.

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.

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.

Objective To investigate the MRI features of the brain in patients with neuromyelitis optica (NMO), and to evaluate the correlation between the brain abnormalities and related risk factors.Methods Fifty-four patients with definite NMO according to 2006 Wingerchuk diagnosis criteria were enrolled in this study. MRI scanning of the brain was performed in these patients. Distribution and signalfeatures of all the lesions were analyzed. A Logistic regression analysis was used to evaluate the risk factors of brain abnormalities. Results Twenty-four NMO patients (44. 4%) showed unremarkable findings and thirty (55.6%) showed abnormalities on brain MRI. Multiple and non-specific small lesions in the subcortical white matter and grey-white matter junction were the most frequent abnormalities on brain MRI (13/30, 43. 3%). Typical lesion locations included corpus callosum, subependyma of ventricles,hypothalamus and brain stem. The lesions showed punctate, patchy and linear abnormal signals. Postcontrast MRI showed no abnormal enhancement in 16 cases. Logistic regression analysis showed that coexisting anto-immune disease or infection history had correlations with abnormalities of the brain on MRI (OR=3.519,P ＜0.05). Conclusions There was a high incidence of brain abnormalities in NMO.Subependymal white matter, corpus callosum, hypothalamus and brain stem were often involved in NMO.NMO patients with coexisting anto-immune disease and infection history had higher risk of brain abnormalities.

ObjectiveTo optimize the b-value of breast diffusion-weighted MRI (DW-MRI) at 1.5T by applying a range of b values and comparing the apparent diffusion coefficient (ADC) and signal-to-noise ratio (SNR) on a phantom,disease-free breast tissues,and benign and malignant lesions.Methods A phantom and 32 women with pathologically confirmed malignant ( 18 ) and benign ( 14 ) lesions were examined using EPI-DWI with different b values on a 1.5 T MR scanner.The b-value of EPI-DWI was 0,50,100,200,400,600,800,1000,1200,1400,1600,1800,2000,2200,2400,and 2600 s/mm2,respectively.The SNR and ADC values of the phantom,disease-free breast tissues,and benign and malignant lesions were measured.The correlation between the b-value and ADC or SNR of each image was analyzed.ResultsThe SNR of DWIdecreased as the b-valueincreased,showing aninversecorrelation (r =-0.802,P ＜0.01 ).The ADC values of benign and malignant lesion decreased as the b-value increased (r =-0.923 and -0.855,P ＜0.01 ).The maximum difference in ADC between malignant and benign lesions was observed when the b-value is between 800 and 1000 s/mm2 and diminished when the b-value was greater than 1400 s/mm2.ConclusionFor good image quality and valid differentiation between malignant and benign lesions,the optimized b-value of DWI at 1.5 T is between 800 s/mm2 and 1000 s/mm2.

0bjective To evaluate the application of whole body MR diffusion weighted imaging (DWI)in the detection of bone metastasis using skeletal scintigraphy as the referenee.Methods Fonv.two healthy volunteers and 38 patients with malignant tumors were enrolled in our studv.A11 the patients received MR examination and skeletal scintigraphy within one week.MR examination was performed on GE signa 3.0T MR scanner using a build.in body coil.The skeletal system Was divided into eight regons and the images of the whole body MR DWI and skeletal seintigraphy were reviewed to compare the two modalities patient by patient and region by region.The images were reviewed separately by two radiologists and two nuclear medicine physicians,who were blinded to the results of another imaging modality.Results A total of 169 metastatic lesions in 69 regions of 30 patients were detected by whole body MR DWI while 156 lesions in 68 regions of 29 patients were identified by skeletal seintigraphy.There were two cases negative in scintigraphy but positive in whole body MR DWI and one case positive in scintigraphy only.There were eight lesions negative in scintigraphy but positive in whole body MR DWI,mainly located in the spine.pelvis and femur.Seven 1esions were only detected by scintigraphy,mainly located in the skull.sternum.clavicle and scapula.Conclusion The whole body MR DWI reveals excellent consistency with skeletal scintigraphy regarding bone metastasis.and the two modalities are complementary for each Other.

Objective To investigate the value of apparent diffusion coefficient(ADC)of breast carcinoma before and one course after neoadjuvant chemotherapy,and to predict the response of breast carcinoma to neoadjuvant chemotherapy.Methods Twenty female patients with 21 breast carcinoma lesions were examined with diffusion weighted imaging(DWI)and contrast-enhanced MRI within 7 days prior to neoadjuvant chemotherapy(adriamycin + taxinol),during 18-21 days after the first couse of therapy and within 7 days prior to the surgery resection.The tumors were divided into response group and relative nonresponse group by change of the tumor.The difference of ADC between the two groups before and after 1st course of chemotherapy was compared.Results In chemotherapy response group with 15 lesions,the mean ADC was(0.98±0.15)×10-3 mm2/s before chemotherapy and increased to(1.22±0.23)×10-3 mm2/s after 1 st course of chemotherapy(P＜0.05),while in nonresponse group with 6 lesions,the mean ADC before and after chemocherapy was(1.09±0.08)×10-3 mm2/s and(1.11±0.07)×10-3 mm2/s,respectively,with no statistical difference(P>0.05).The mean ADC of response group prior to chemotherapy was significantly lower than that of nonresponse group(P＜0.05).A significant negative correlation(r=-0.51,P＜0.05)was observed between the ADC prior to treatment and change of ADC after the first couse therapy.Conclusion Preliminary results revealed the initial ADC of the tumor in patient with breast carcinoma and the changes of ADC after 1 st couse treatment may predict response to neoadjuvant chemotherapy.

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.