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Objective@#To investigate the correlation of functional connectivity (FC) and the integrity of connective fibres between hippocampus and thalamus in Alzheimer′s disease(AD) and amnestic mild cognitive impairment (aMCI).@*Methods@#Both resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) data of 40 AD patients, 37 aMCI patients and 41 normal control subjects matching with age and educational level were collected. These subjects were all recruited from outpatient Department of Neurology in the Second Medical Center of Chinese PLA General Hospital, as well as poster, from May 2016 to January 2018. The FC strength between bilateral hippocampus and thalamus, as well as the parameters representing integrity of connective fibres, including fractional anisotropy (FA) and mean diffusivity(MD),were analyzed. Also, the correlations between FC strength and FA or MD strength were analyzed in the study.@*Results@#Compared to that of normal control subjects, the FC strength between billateral hippocampus and thalamus in patients with AD, aMCI were not significantly different(P>0.05). The integrity of bilateral connective fibres between hippocampus and thalamus were damaged in AD patients when compared to normal control subjects(P<0.01). A positive correlation of connective fibres integrity with FC strength between hippocampus and thalamus was found in the left side(r=0.25,P<0.05) but rather in the right side.@*Conclusion@#In AD and aMCI patients, structural connectivity between left hippocampus and thalamus affects the functional connectivity between them.
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Objective To investigate the value of 3D pseudo-continuous arterial spin labeling (3D-pCASL) magnetic resonance perfusion technique in evaluating posterior circulation ischemia (PCI) of the elderly beyond 80 years old and to offer the evidence of PCI of the elderly for clinical diagnosis. Methods Totally 53 male subjects older than 80 years were recruited in this study,including 20 subjects with clinically diagnosed PCI and 33 normal subjects. All the subjects underwent routine brain magnetic resonance imaging and 3D-pCASL sequence on a 3.0T magnetic resonance imaging system with 8 channel brain coil. Two post-labeling delay (PLD) time (PLD=1525 ms and PLD=2525 ms) of 3D-pCASL were used in this study to increase the accuracy of cerebral blood flow (CBF) change of posterior circulation region. We used SPM12 software to measure mean CBF values of bilateral occipital lobes and bilateral cerebellums. Independent sample t-test and rank-sum test were performed to evaluate the difference of CBF changes of anterior circulation and posterior circulation in two groups at two PLD time,the difference of CBF changes of bilateral occipital lobes and bilateral cerebellums in two groups of two PLD time,and the difference of increment of CBF between two PLD interval between two groups. Results In case group,the CBF value of the anterior circulation was significantly higher than that of posterior circulation at both two PLD time points (PLD=1525 ms and PLD=2525 ms)(P=0.000,P=0.000);in control group,the CBF value of the anterior circulation was significantly higher than that of the posterior circulation only at PLD=1525ms (P=0.025). The CBF values at bilateral occipital lobes and bilateral cerebellums at two PLD time points (PLD=1525 ms and PLD=2525 ms) were significantly higher in case group than in control group(P=0.003,P=0.002,P=0.000,P=0.001,P=0.000,P=0.001,P=0.002,P=0.014,respectively). Compared with the control group,the difference was statistically significant in bilateral occipital lobes and cerebellums with a smaller △CBF between two PLD interval in case group (P=0.004,P=0.001,P=0.001,P=0.025). Conclusion Multiple PLD time points need to be used in 3D-pCASL in diagnosing PCI of the elderly because the posterior circulation is slow in these patients. 3D-pCASL technique is sensitive in detecting decreased CBF in posterior circulation and therefore can be used to predict posterior circulation stroke in the elderly.
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<p><b>OBJECTIVE</b>To evaluate the diagnostic efficacy of IFIR-FIESTA technique in detecting renal artery stenosis in elderly patients.</p><p><b>METHODS</b>Twenty-seven aged patients underwent both IFIR-FIESTA and 3D CE-MRA examinations. The imaging quality and renal artery stenosis grades were evaluated. Kappa test was used to assess the consistency between the two methods. With CE-MRA as the reference, the diagnostic sensitivity, specificity, accuracy, PPV and NPV for IFIR-FIESTA were calculated in detecting renal artery stenosis.</p><p><b>RESULTS</b>The images by the two methods were 100% qualified for diagnosis, although the image quality of CE-MRA was significantly better. IFIR-FIESTA and CE-MRA showed excellent consistency in detecting renal artery stenosis. With CE-MRA as the reference, the diagnostic sensitivity, specificity, accuracy, PPV and NPV for IFIR-FIESTA were 97.1%, 100%, 98.1%, 100%, and 95% in detecting renal artery stenosis, respectively.</p><p><b>CONCLUSION</b>IFIR-FIESTA is feasible as a routine examination for detecting renal artery stenosis in elderly patients.</p>
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Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Contrast Media , Feasibility Studies , Magnetic Resonance Angiography , Methods , Renal Artery Obstruction , Diagnosis , Sensitivity and SpecificityABSTRACT
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.
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Objective To study the functional connectivity (FC) pattern of thalamus in patients with Alzheimer' s disease (AD).Methods In the present study,resting state functional magnetic resonance imaging (MRI) data were obtained from 30 patients with AD and 26 subjects with normal cognition (NC).The altered functional connectivity pattern in AD was evaluated by comparing to NC.Then a correlation analysis was performed between the strength of FC of the identified regions and various clinical variables for evaluating the relationships between the strength of FC and the cognitive abilities (MMSE,immediate recall and delayed recall of Auditory Verbal Learning Test) of the AD patients.Results The MMSE(19.7 ± 4.1),immediate recall (2.8 ± 1.7) and delayed recall (0.7 ± 1.3) of Auditory Verbal Learning Test in AD patients were lower than NC group (28.8 ± 1.0,5.9 ± 1.2,5.7 ± 2.2 ; t =11.09,8.09,10.51,all P ＜0.05).Compared to NC,AD patients showed decreased FC between the left thalamus and several regions of brain including right posterior/middle cingulate cortex (PCC/MCC.R),left medial prefrontal cortex (MPFC.L) and right superior frontal gyms/medial prefrontal cortex (SFG/MPFC.R).For the right thalamus,decreased FC was found in SFG/MPFC.R,PCC/MCC.R and right hippocampus.We also found increased FC between the bilateral thalamus and many regions of brain including inferior temporal gyrus,medial temporal gyrus,SFG,postcentral gyrus,paracentral lobule,inferior frontal gyms and insula.Significant correlations between the fitted FC strength and clinical variables were also detected.Conclusions FC pattern of thalamus in AD group is impaired.Increased FC in AD may indicate the presence of a compensatory mechanism.The alteration is related with cognitive function in AD.
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ObjectiveTo investigate the characteristics of spontaneous activities throughout the whole brain with Alzheimer's disease (AD) by resting state functional magnetic resonance imaging ( fMRI ).Methods The subjects included 23 AD patients and 21 normal controls (NC),who underwent a neuropsychological test battery including MMSE and Auditory Verbal Learning Test (AVLT) and restingstate fMRI using GE Signa 3.0 T MR scanner.The neuropsychological scores were compared between two groups.Regional homogeneity (ReHo) method was used to explore the different regional spontaneous activities throughout the brain between normal controls and patients with AD.Results In AD group,clinical variables (MMSE scores:20 ±4,AVLT-Immediate Recall:2.6 ± 1.6,AVLT-Delay Recall:0.4 ±0.7,AVLT-Recognition:5.8 ± 3.7 ) were lower than NC group( 29 ± 1,5.9 ± 1.2,5.5 ± 2.0,9.2 ± 1.1,T =10.58,7.21,10.99,3.96,all P ＜ 0.01 ).With the threshold of P ＜ 0.01 for each voxel and a cluster size of at least 100 voxels,decreased ReHo indexes were found in default mode network (DMN) including the medial prefrontal cortex,posterior cingulate gyrus/precuneus,right superior temporal gyrus and bilateral superior parietal lobule/inferior parietal lobule in AD,while increased ReHo indexes were found in left putamen and thalamus compared with controls.ConclusionThe DMN are damaged in AD and spontaneous activities of putamen and thalamus are reinforced as compensation response of subcortical structures.
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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.
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Objectives To measure the microstructural differences in the brains of participants with amnestic mild cognitive impairment ( aMCI) and compare with a control group using a magnetic resonance diffusion tensor imaging ( DTI) technique with fully automated image analysis tools. Methods A standardized clinical and neuropsychological evaluation was conducted on each subject 31 participants (15 participants with aMCI, 16 healthy elderly adults) underwent magnetic resonance imaging (MRI)-based DTI. To control the effects of anatomical variation, the diffusion images of all participants were registered to standard anatomical space. Voxel-by-voxel comparisons showed significant regional reductions in white matter regions of fractional anisotropy (FA) in the participants with aMCI as compared with the controls. Results Significantly decreased FA value measurements (P<0. 001) were observed in the right frontal white matter in participants with aMCI. Moreover, there was a statistically significant difference between the patients with aMCI and controls in considering the small regions of bilateral superior frontal gyrus white matter (P < 0.001). Conclusions White matter damage of frontal lobe may play an important role in histopathologic changes associated with amnestic mild cognitive impairment
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Objective To identify the characteristics of hippocampal 3-dimensional MRI in patients diagnosed as having subtypes of amnestic mild cognitive impairment(aMCI)using hippocampal surfacebased analytic technique.Methods Fifry aMCI patients and 16 healthy controls who were equivalent in age and education(NC)were recruited.Every subiect carried out a 3-dimensional MRI scan.After the imaging data were acquired.the borders of the hippocampus were manually traced in coronal vlew using the software of InsightSNAP1.4.1. Hippocampal volume was computed automatically and statistically analysed.Hippocampal 3-dimension MRI were transformed into 3-dimension parametric surface mesh models of 400×200 prids.Hippocampal radial distance measures which was the distance from the surface point to the central axis were statistically compared between two groups.The radial atrophy significance maps were acquired and adjusted for multiple comparisons.Hippocampal morphological difference maps of aMCI in contrast with NC were acquired.Results The average normalized volume of left hippocampus were(3247.5±600.2)mm3 in aMCI patients and(3467.9±451.3)mm3 in NC subjects.The average normalized volume of right hippocampus were(3416.8±699.1)mm3 in aMCI patients and(3469.1±358.9)mm3 in NC subjects.Comparison of hippocampal volume did not differ significantly between aMCI patients and NC subjects(t=1.161,P=0.255;U=0.178,P=0.859).By using hippocampal surface-based morphologic analytic technique,3-dimension hippocampal morphological difference maps between two groups were acquired,showing significant atrophy on the lateral and inferior hippocampal surface which corresponded to CA1 and subiculum hippocampal subfields bilaterally in aMCI patients compared with NC subjects. Conclusions aMCI patients do not have significant volume loss in the hippocampus. Through hippocampal surface-based morphologic analyses, partial regional atrophy of hippocampus at some degree is found, mainly localizing in the lateral and inferior hippocampal regions which correspond to CA1 and subiculum hippocampal subfields bilaterally in aMCI compared with NC. These results may reflect the early image marker in aMCI.
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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.
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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.
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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.
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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.
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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