DWI And LAVA Dynamic Enhanced MR In The Differentiating Between Pancreatic Carcinoma And Chronic Pancreatitis

Objective:To investigate DWI and LAVA dynamic enhanced MR indifferentiating the pancreatic carcinoma(PC) and the chronic pancreatitis(PC).Comparing the difference of the ADC value,time intensity curve (TIC),theenhancement ratio of arterial phase relative signal increase (ARSI%) and maximumrelative signal increase (MRSI%) to improve the diagnostic level.Materials and Methods:This retrospective study includes the patients who wereadmitted between April2011-April2012in1staffiliated hospital of Dalian medicaluniversity. The diagnosis of PC and CP were proved histologically after surgery、imaging guided biopsy and typical clinical manifestations. This study includes22casesof PC (M:F=14:8, mean age=65±11years) and14cases of CP (M:F=11:3,meanage=58±10years).14cases of normal pancreas (normal physical examination) weretaken for normal control group(M:F=8:6,mean age62±8years).Subjects wereevaluated with DWI (b=600s/mm2) and LAVA dynamic enhanced MR at1.5-Tsuperconducting MR unit (GE Signa Excite1.5T, GE Healthcare). The apparentdiffusion coefficient (ADC) values of PC, CP and normal pancreas were measured. AlsoDynamic enhanced MR was used in selecting the region of interest (ROI), drawing theTIC and to calculate the enhancement ratio of ARSI%and MRSI%. Care was taken toavoid measuring ADC of pancreatic ducts, cystic lesions, necrosis and artifacts withinthe region of interest. The statistical method used was Independent samples t test by theSPSS11.5. p <0.05indicated statistically significant.Results:On b=600s/mm2DWI, PC was hyperintense in18cases and remaining4cases showed same intensity with normal pancreas. CP was hyperintense in12casesand2cases showed same intensity as remaining pancreatic tissue. Comparing PC andNP, the mean ADC values were0.00145±0.00014and0.00207±0.00024respectivelyand p value was0.002. Comparing CP and NP, the mean ADC values obtained were 0.00172±0.00016and0.00207±0.00024and p value was0.017. Finally between PC andCP the mean ADC values were0.00145±0.00014and0.00172±0.00016and p valuewas0.004. There was significant difference of ADC values between the PC and CP. Inthe LAVA dynamic MR sequence by selecting the ROI,3types of curve were obtained.In curve type1(slow up and plateau),5cases of pancreatic carcinoma and5cases ofchronic pancreatitis were seen. In Type2curve (slow up and slow down),14cases ofPC and2cases of CP were seen. In Type3curve (slow rise),3cases of PC and7casesof CP were obtained,2=9.281,p=0.01. The contrast enhancement ratio ARSI%in PCwas54.4%, and for CP it was43.6%(p=0.551).The MRSI%in PC was123.7%andfor CP was135.7%(p=0.009).Conclusion:ADC value of pancreatic carcinoma was less than the chronicpancreatitis, showed significant difference between them.1. The TIC of most pancreatic carcinoma was type2(slow up and slow down) andmost of the chronic pancreatitis was type3(slow rise), showed significant differencebetween them.2. The MRSI%in pancreatic carcinoma was less than chronic pancreatitis, showedsignificant difference between pancreatic carcinoma and chronic pancreatitis.3. DWI and LAVA dynamic enhanced MRI are helpful in differentiating thepancreatic carcinoma and chronic pancreatitis.