Initial Study Of Diagnostic Value In Diffusion Weighted Imaging Of Colon Cancer

Objective To investigate the ability of diffusion-weighted imaging in displaying colon cancer when b values are different, and determine reasonable b values of DWI of colon cancer; and investigate the relationship between ADC values and cell differentiation degree and T staging of colon cancer, and offer more information for clinical treat.Methods Thirty patients with colon cancer who are diagnosed by colonoscope are applied by routine method and DWI of different b values at 1.5T MR scanner before operation. First to measure all signal intensity values of tumors and normal bowels and background noise in DWI and T2,then the mean apparent diffusion coefficient values and signal-to-noise ratio (SNR) of tumors,contrast-to-noise ratio(CNR)of tumors and normal colon wall were calculated and compared. All patients confirmed by operation and pathology are graded and by T staging , then ADC values of tumors of different grading and T staging are compared.Results The CNR of tumors and normal colon wall in DWI decrease following the ascensusing of b values, the CNR of DWI is better than T2 when b valves are 400～1200 s/mm2, the CNR of b1000 is better than b1200,and it is of statistical significance,(F=36.289,P<0.05).The SNR of tumors decreases following the ascensusing of b values, the SNR of DWI is better than T2 when b valves are less than or equal to 800( P<0.05), and it is of statistical significance. The SNR of DWI of tumors when b value is 1200 s/mm2 is inferior to T2.The ADC values of tumors shrinks following the ascensusing of b values, the results of the ADC values of different b values compared are of statistical significance ,when b valves are less than or equal to 800 (F=12.863,P<0.05), the ADC values of different grading tumors compared are of statistical significance( P<0.05),it resides in well-differentiated and moderately differentiated, in well-differentiated and poorly differentiated, and the ADC values of tumors degrades following degrading of cell differentiation .The comparison of the ADC values of different T staging is not statistically significant.Conclusion It is not only to obtain a better image quality but also obtain more accurate ADC value when b value is 1000s/ mm2. The ADC values of tumors shrinks following the ascensusing of b values, the ADC value of colon cancer is correlated with malignancy degree of tumors, the ADC values of tumors degrades following degrading of cell differentiation, the ADC value can become an index of colon cancer diagnosing and estimating prognostic level.