ABSTRACT
Objective To analyze and evaluate changes of the brain gray matter in patients with Parkinson's disease (PD).Methods 46 patients with PD and 19 normal control(NC) subjects(matched to the patients in age and gender) were selected in this study.46 cases of PD were divided into early PD group(ePD,25 cases) and middle-advanced PD group(maPD,21 cases) by improved Hoehn-Yahr(H-Y) stages.All the subjects underwent 3.0T MR scanning,and data of high resolution T1-weighted imageing (T1WI) were acquired.Gray matter volume differences between PD group and NC group,or ePD group and maPD group were assessed by voxel-based morphometry (VBM) combined diffeomorphic anatomical registration through exponentiated lie (DARTEL) method.Results The gray matter volume of the bilateral frontal lobes, temporal lobes, insular lobes, cingulum gyrus, hippocampus, fusiform gyrus, cerebellum and right cuneus lobe and precuneus lobe in the PD group was smaller than that in the NC group.The gray matter volume of the bilateral frontal lobes, temporal lobes,insular lobes,cingulum gyrus,rectus gyrus,lingualis gyrus,fusiform gyrus,hippocampus,amygdaloid and cerebellum in the maPD group was smaller than that in the ePD group.Conclusion VBM reveals a widespread volume reduction of the gray matter in PD patients,and detectes a correlation with disease duration and severity.These changes located in special distribution may be in line with the pathology of PD.
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Objective To evaluate the diagnostic accuracy of contrast-enhanced MR angiography (CE MRA) in infrapopliteal occlusive diseases of diabetic patients.Methods A total of 105 patients with known diabetes and peripheral vascular occlusive disease who underwent both CE MRA and DSA examnations were included in this study.They had no obvious stenosis or with stenosis of less than 75％ in iliac,femoral,and popliteal arteries.Every infra-popliteal artery was anatomically divided into 9 vascular segments as tibiofibular trunk artery,proximal and distal anterior tibial artery,proximal and distal posterior tibial artery,proximal and distal peroneal artery,plantar and dorsalis pedis artery.There were 945 segments.The arterial stenosis was accessed with CE MRA and DSA respectively.The segments were scored in 5 categories as＜30％,≥30％ and＜50％,≥50％ and＜75％,≥75％ and＜100％,and 100％ according to stenostic degrees.The Kappa test was used to compare the diagnostic consistency of CE MRA and DSA.Taken DSA as a gold standard for reference,ROC curve was drawn to calculate the diagnostic accuracy of CE MRA in diagnosis of lower limb arterial disease.Results The ratio of statistically valid segments for both CE MRA and DSA were 97.7％ (923/945) in 945 vessel segments of 105 patients,and 390 of 923 arterial segments were both indicated as occlusion by CE MRA and DSA.The diagnostic consistency for the segments was listed in the decreasing order as follows:proximal peroneal artery,proximal posterior tibial artery,distal posterior tibial artery,proximal anterior tibial artery,distal anterior tibial artery,tibiofibular trunk artery,dorsalis pedis artery,plantar artery,distal peroneal artery,and corresponding Kappa values were 0.88,0.86,0.84,0.84,0.81,0.77,0.75,0.75 and 0.73,P＜ 0.05.The AUC(area under ROC curve) of CE MRA was 0.893 with 95％ confidence interval of 0.882 to 0.904.Conclusion CE MRA is an accurate imaging modality in the diagnosis of infrapopliteal occlusive disease s for diabetes.
ABSTRACT
Objective To evaluate the feasibility and diagnostic accuracy of CE-MRA with low dose contrast agent by comparison with DSA in diabetic patients with peripheral arterial diseases. Methods ( 1 )Study in vitro: test tubes containing Gd-DTPA of different concentrations were scanned, and the relationship between signal intensities and concentrations of GD-DTPA was analyzed. DSA and CE-MRA with selected concentrations of Gd-DTPA were performed on stenotic vascular models to estimate the proper low dose of GD-DTPA for clinical applications. (2) Clinical applications: 78 diabetic patients with peripheral arterial diseases were scanned from the abdomen and pelvis station to the calf-foot station in a 3 T MR system with standard bolus chase 3D CE-MRA sequence after injection of 13 ml GD-DTPA . The image quality,diagnostic rate of stenosis of arteries in calf and degree of venous contamination were evaluated with Fisher's exact test. DSA images of 220 vascular segments in 22 patients ( 10 segments per patient) were acquired as the gold standard and compared with CE-MRA by using Kappa test. Results The MR signal intensities were proportional to the concentrations of contrast agent in present study, and all stenotic segments of vascular model were displayed by CE-MRA with GD-DTPA at lower concentration of 1.5 mmol/L. As for MRA images of 78 diabetic patients with low dose Gd-DTPA, about 97.4% (76/78) showed diagnostic image quality for pelvic and thigh stations. But the MRA images of lower extremities were interfered by the venous contamination significantly (P ＜ 0.01 ). Compared with DSA for 22 patients, the diagnostic sensitivity, specificity and agreement coefficient (Kappa value) of MRA were 96. 0% ( 168/175), 73.3%(33/45), and 0.72 (P＜0.01), respectively. Conclusion Using 3.0 T MR scanner, high quality CE-MRA of lower limb arteries can be obtained for clinical applications with contrast agent dose as low as 13 ml,which has comparable diagnostic sensitivity and specificity with DSA. But the limitation of venous contamination in MRA image should be resolved in further studies.