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ObjectiveTo investigate the value of diffusion tensor imaging (DTI) at high b value for unilateral middle cerebral artery (MCA) occlusive disease in patients without obvious infarct lesions on conventional MR imaging.MethodsDTI at high b value (2200 s/mm2 ) was performed using a 3.0 Tesla MR scanner in 34 patients with unilateral middle cerebral artery occlusion,who had no obvious infarct lesions on conventional MR imaging. Fractional anisotropy (FA),apparent diffusion coefficient (ADC),axial diffusivity (eigenvalue λ1) and radial diffusivity (eigenvalues λ2,λ3) were measured at the ipsilateral and contralateral corona radiata,anterior and posterior limbs of the internal capsule,cerebral peduncle and pons in all subjects.Mean ADC,FA,λ1,λ2 and λ3 values of corona radiata,anterior and posterior limbs of the internal capsule,cerebral peduncle and pons were compared between the ipsilateral and contralateral MCAterritory by t test. Results Among the 34 patients,left MCA occlusion in M1 segment occurred in 16 patients and right MCA occlusion in Ml segment occurred in 18 patients.At the ipsilateral corona radiata,mean FA,ADC,λ1,λ2 and λ3 were 0.419 ±0.032,(5.975 ±0.272) × 10 3,(5.704 ±0.365) ×10-3,(6.412 ±0.368) × 10-3 and (6.605 ±0.343) × 10-3 mm2/s,respectively.At the contralateral corona radiata,mean FA,ADC,λ1,λ2 and λ3 were 0.443 ± 0.033,(5.804 ± 0.282) × 10 -3,(5.651 ±0.350) × 10-3,(6.099 ±0.353) × 10-3 and(6.372 ±0.355) × 10-3 mm2/s,respectively.At the ipsilateral corona radiata,mean FA was significantly decreased(t =11.614,P ＜0.01),and mean ADC (t=12.421,P＜0.01),λ1(t =7.447,P＜0.01),λ2(t=10.244,P＜0.01) and λ3(t=9.890,P＜0.01) were significantly increased.At the ipsilateral anterior and posterior limb of the internal capsule,mean FA were 0.609 ±0.026 and 0.674 ±0.033,λ1 were(5.330 ±0.462) × 10 -3 and(5.171 ±0.456) ×10-3 mm2/s,respectively.At the contralateral anterior and posterior limb of the internal capsule,FA were 0.622 ±0.026 and 0.694 ±0.034,λ1 were(5.064 ± 0.448) × 10 -3 and(4.924 ± 0.365) × 10 -3 mm2/s,respectively.Mean FA was significantly decreased (t =7.823,8.013,all P ＜ 0.01) and mean λ1 was significantly increased (t =7.811,8.800,all P ＜0.01) at the ipsilateral anterior and posterior limbs of the internal capsule.There was no significant difference in ADC,λ2 and λ3 value between the ipsilateral and contralateral sides.And all the DTI parameters,including mean ADC,FA,λ1,λ2 and λ3 values,showed no statistical difference between both sides of cerebral peduncle and pons.ConclusionDTI at high b valuc can provide useful information for visualizing ischemic white matter injury in patients without obvious infarct lesions on conventional MR imaging.
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Objective To explore the role of proton MR spectroscopic imaging(1H-MRSI)and diffusion tensor imaging(DTI)in the diagnosis of adrenoleukodystrophy and to demonstrate the involvement of fibers by using the technique of DTT.Methods 1H-MRSI,DTI and routine imaging examinations were performed in 6 patients with ALD.The values of NAA,Cho,Cr,ADC,and FA were evaluated in different regions of lesion.The involved fibers were demonstrated by using the technique of DTT.Results The ratios of NAA/Cr(0.55±0.19)and NAA/Cho(0.22±0.11)were lower(F=7.693,7.751),and Cho/Cr(2.54±0.37)was higher(F=6.348)in the initial lesions,where higher ADC values(1.49±0.36,F=5.226)and the lowest FA values(0.21±0.08,F=5.139)were also observed(P＜0.05).The decreases of NAA/Cr(1.16±0.03)and NAA/Cho(0.45±0.17)in adjacent regions were more distinct than those of remote regions(t=1.769,1.842,P＜0.05).In the developing regions,the ADC values(0.89±0.03)were lower and the FA values(0.45±0.07)were the highest.There was negative correlation between NAA/Cho and ADC values(r=-0.71,P＜0.05),and there was positive correlation between NAA/Cho and FA values(r=0.31,P＜0.05).Discontinuations and fragments of fibres were observed in corpus callosum and pyramidal tract.Conclusions Combination of 1H-MRSI and DTI can offer a sensitive method for the early diagnosis and monitor the progress of white matter.DTT can be used to directly observe the involvement of fibers.
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Objective To evaluate the usefulness of MRI in the diagnosis of adenomyosis. Methods Sagittal Turbo SE T 1WI, T 2WI, T 1SPIR and T 2SPIR MRI examination were performed on 30 cases with adenomyosis. Results The lesions in 12 cases with diffuse adenomyosis were demonstrated as diffusely thickened junctional zone (JZ) measured 10～35 mm (mean 18 mm) On T 2WI. 6 of them were of homogenous hypointensity. Another six had hyperintensive foci within the hypointensive lesions on T 2WI, and these hyperintensive foci could also be found on T 1WI in 5 lesions. 23 focal lesions (adenomyomas) in 18 cases were oval, irregular or round masses with hypointensity that were the same as the intensity of JZ on T 2WI. They were from 2.0-7.5 cm in diameter (mean 3.9 cm), and all but one showed ill-defined margins. 15 masses hadhyperintensive foci within the hypointensive lesions on T 2WI and 12 of 15 presented hyperintensity on T 1WI. The diffusely thickened JZ and focal masses correspond to the hyperplastic and hypertrophic musculature around the heterotopic endometrial islands. The hyperintensive foci were correlated with the heterotopic endometrial islands. The hyperintensive foci showed only on T 2WI corresponded to the heterotopic endometrial islands without hemorrhage. The hyperintensive foci shown on both T 2WI and T 1WI were the heterotopic endometrial islands with hemorrhage. Conclusion MRI is the modality of choice for the diagnosis of adenomyosis. T 2WI is the most useful sequence. T 2WI combining with T 1WI, T 1SPIR, and T 2SPIR can improve the accuracy in the diagnosis of adenomyosis.
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Objective:To evaluate the value of the preoperative T staging of laryngeal and hypopharyngeal cancers by MRI at high field strength(1.5T).Methods:The MRI data of 36 cases of primary laryngeal or hypopharyngeal cancers were retrospectively staged,and compared with the clinical and postsurgical pathologic staging.Results:The accuracy of staging in each T stage of laryngeal and hypopharyngeal cancers was:T1:92%;T2:86%;T386%;T4:100% by MRI vs.T1:100%;T286%;T3:57%;T4:22% by clinic/laryngoscope.The total accuracy of MRI and clinic/laryngoscope respectively was 92% vs 69%.P＜0.05.Conclusion:MRI can correctly depict the original tumors site and invasion extension of laryngeal and hypopharyngeal cancers by comparing T1WI and T2WI with multiplanar,consequently improve the accuracy for staging significantly.
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Objective The purpose of this study was to provide practical anatomic data for the imaging diagnosis and surgical treatment of the disease of the subphrenic spaces. Methods Sectional anatomy of the subphrenic spaces on the coronal plane were investigated on 30 sets of serial coronal sections of superior abdomen of Chinese adult cadavers and MR imaging of 2 abdomen of cadavers. Results Subphrenic spaces were divided into perihepatic spaces and perisplenic spaces on the coronal plane.The space between the anterior margin of left gastropancreatic fold and the posterior layer of hepatogastric ligament is the only direct communication between the superior and inferior recesses of the lesser sac.Its communicating type is divided into three types on the coronal plane.The right layer of the gastrophrenic ligament is continuous with the posterior layer of the lesser omentum,the left layer of the gastrophrenic ligament is continuous with the right layer of the phrenicosplenic ligament and the posterior layer of the gastrosplenic ligament.Left gastropancreatic fold is continued to the left and right layers of gastrophrenic ligament upward.The bare area of stomach is located between the left and right layers of gastrophrenic ligament,its existing rate is 100%.The bare area of spleen is located among phrenicosplenic ligament,gastrosplenic ligament,splenorenal ligament and splenocoloic ligament.Its the most width exists at the splenorenal ligament.It is divided into the part of the splenic hilus and the splenorenal part.Its maximum is 2 64?1 16 cm,4 16?2 24 cm respectively. Conclusion The coronal plane is dominant for showing left gastropancreatic fold and the communication relationship between superior and inferior recesses of the lesser sac.The superior and inferior recesses of the lesser sac that may communicate with each other is 73 3 percent of all the cases studied