| Part one: Experimental study on liver MR Diffusion weightedimaging best techniquesObjective: To study the optimal technology of liver MRdiffusion-weighted imaging.Materials and Methods: DWI and measurement of mean apparentdiffusion coeffecient (mADC) value, exponential apparent diffusioncoefficient(eADC), signal to noise ratio (SNR) and Image quality index(QI) were performed in 24 healthy subjects by changing TR value and bvalue and different coil and Nex at 1.5T Twinspeed MRI. (GE SignaHorizon LX, USA),Data were analyzed by SPSS 12.0.Results:(1) With TR value increased, the mADC, eADC, qualityindex and SNR were insignificantly different (P＞0.05). (2) With b valueincreased, the mADC decrease,eADC increase, quality index and SNRof Body coil decrease, significantly different (P＜0.05). (3) With b valueincreased, the mADC of Gpflex coil decrease, significantly different(P＜0.05).but the eADC increase, quality index and SNR decrease,insignificantly different (P＞0.05). (4) With Nex value increased, themADC, eADC, quality index and SNR were insignificantly different (P＞0.05).but spend more scan time (5) compared Body coil with Gpflexcoil, both had no influence on the value of mADC,eADC. The SNR ofGpflex coil was bigger than the SNR of Body coil,but QI was smallerwhen Gpflex coil was used than that when Body coil was used. Bothuseful for liver DWI.Conclusions: The higher the b value became theworse the quality of the DWI. As b value increased, mADC valuedecreases, eADC increases.the quality index and SNR of Body coil andGpflex coil decreases. The SNR of Gpflex coil was bigger than the SNRof Body coil,but QI was smaller when Gpflex coil was used than thatwhen Body coil was used. Both useful for liver DWI,b value b=00, TR4000, 1 NEX, Body coil or Gpflex coil, slice 8mm,space 1.5mm, abreath-hold period are very important Parameters in DWI scanning to get Appropriate imaging on 1.5T MR.Part two The investigation and clinical application of MRdiffusion weighted imaging in differential diagnoses of focal liverlesionsObjective: To investigate clinical application of MR diffusion weightedimaging (DWI) in differential diagnoses of focal liver lesions.Materials and Methods: DWI and routine non-enhanced MRI wereused in 91 patients with suspected hepatic lesions, and dynamic contrastenhanced MRI were performed in some typical cases, the b values wereset at 500 s/mm~2. After having collected definitively diagnosable cases,the images of of mean apparent diffusion coefficient (mADC) andexponential apparent diffusion coefficient (eADC) were acquired fromMRI machine software, four items—mADC, eADC, The ratio of mADCvalues in lesion/liver, The ratio of eADC values in lesion/liver—weremeasured.then One-way analysis of variance (ANOVA) was applied tocompare different groups of liver foci with the same item, further, leastsignificant difference test (LSD test)was utilized to multiply comparemeans in those groups where the mean difference was significantstatistically.Results: 1. mADC in different groups: normal liver lower tocyst(P＜0.05) and hemangioma(P＜0.05), but higher to hepaticcarcinoma(P＜0.05); cyst higher to hemangioma(P＜0.05) and hepaticcarcinoma(P＜0.05); hemangioma higher to hepatic carcinoma(P＜0.05).2. eADC in different groups: normal liver higher to cyst(P＜0.05), butlower to hemangioma(P＜0.05) and hepatic carcinoma(P＜0.05); Cystlower to hemangioma(P＜0.05) and hepatic carcinoma(P＜0.05);hemangioma lower to hepatic carcinoma(P＜0.05).3. The ratio of mADC values in lesion/liver value in different groups: cyst higher to hemangioma(P＜0.05) and hepatic carcinoma(P＜0.05);hemangioma higher to hepatic carcinoma(P＜0.05). 4. The ratio of eADCvalues in lesion/liver value in different groups: cyst lower to hemangioma(P＜0.05) and hepatic carcinoma(P＜0.05); hemangioma higher to hepaticcarcinoma, but insignificantly(P＞0.05).Conclusions. DWI is advantage to detect focal liver lesions, and thedifferential diagnoses can be improved hetpful by comprehensivelyutilizing those items such as mADC and eADC... |
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