Abstract:
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Purpose: Comparing conspicuity and image quality of acute and subacute cerebral infarctions on DWI image with different b values in the first 3T MR scanner in China, in order to determine the optimum b-value for diffusion weighted imaging. The second aim of our study is to evaluate the ability of detecting fresh lesions in patients with recurring infarctions by the DWI image with the b value of best SNR, CNR and ADCr.
Methods and Materials: 24 patients (mean 56.6 years old )with acute and subacute infarction were prospectively studied using DWI with b values of 1000,1500,2000,2500 and 3000 on GE 3T MR scanner. All lesions were confirmed by follow up MR examination. Scan parameters included 128x128 matrix, 16 sections, 1 NEX, b value/TR/TE as follows: 1000/7000/71.7; 1500/7000/78.5; 2000/7000/83.9; 2500/7000/88.4; 3000/7000/92.4. SNR, CNR and ADCr of different b values were compared. Then, two experts evaluated the ability of DWI of b value with the best SNR in distinguish fresh lesion from old infarctions in recurring patients comparing T2WI.
Results: All acute and subacute lesions were with hyperintense signal intensity on all DWI images. With b value increasing, the mean contrast of the lesions increased(mean CNR of b 3000=0.5207), with p<0.05; while the SNR significantly decreased correlated with p<0.01(mean SNR of b 1000=112.0576). There were no significant difference among ADCr of different b value, p>0.05. In recurring patients, the ratios of fresh and old lesions SNR was 2.43 for DWI (b=1000) and 0.79 for T2WI, P<0.05 by t-test.
Conclusion: For the different b-values from 1000 to 3000, the DWI image with b=1000 has the best SNR. With b-values increased, DWI image with b=3000 has the most significant conspicuity. DWI with b=1000 was superior to T2WI in detecting fresh lesions in recurring ischemic stroke patients.
Questions about this event email: sdliangjingjing@yahoo.com.cn
Hilian MD, Z,
Comparison Study of Diffusion-weighted Imaging with Different B-values of Cerebral Ischemic Lesions in 3T. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3108577.html
