A Comparative Study Of18F-FDG PET/CT And WB-DWI In The Diagnosis And Staging Of Benign And Malignant Tumors

Objective: The morbidity and mortality of tumor increased gradually，earlydetection of tumors and accurate tumor staging are the key to improve tumortreatment。We have¹⁸F-FDG PET/CT as the standard，and investigate the WB-DWIand PET/CT in tumor qualitative as well as staging whether a significant difference。In order to more effectively guide the clinical situation depending on the type of tumorand metastasis to select the appropriate inspection methods to improve the accuracy ofthe stage at diagnosis，and to provide a reliable basis for treatment。Materials and Methods:45patients in our hospital between August2012toFebruary2013,1cases of laryngeal tumors、breast tumors，lung tumors in26cases,2cases of pancreatic tumors，2cases of kidney tumors，2cases of intestinal disease，5cases of Female reproductive system tumors，1cases of bladder tumor，2cases of liverlesions，three cases were diagnosed by PET/CT as benign lesions。All patients werechecked by PET/CT and WB-DWI within a week， without any treatment。The scopeof the inspection from the head to the upper femur level, not a fixed sequence of twochecks。PET/CT scan used a GE Discovery PET/CT machine。WB-DWI scan useda GE Singa HDx1.5T MRI。PET’s images reconstruction using ordered subsets expectation maximizationiteration （OS-EM） method，the image attenuation correction using CT scan data。Allpatients fasted for more than six hours before the examination， glycemic wascontrolled less than10.0mmol/L。Intravenous injection of¹⁸F-FDG agent0.12a0.15mCi/kg，drinking about800ml after the injection，quiet、dark state have a rest of50-60minutes，then make a whole body scanning，make the bladder empty before thescaning，and drinking water about400ml， in order to optimize the expansion of thegastrointestinal tract。When it is necessary，we make a local delayed imaging abouttwo hours after the injection of the imaging agent， to exclude the effects of inflammatory lesions and gastrointestinal physiological uptake， or due to differenthistological type and degree of differentiation，¹⁸F-FDG slower uptake rate andproduce false-negative results。When PET/CT scaning，the patient supine position，the low-dose spiral CT scan first，the parameters:140kv,80mA, pitch6:1, slicethickness5mm, interval4.25mm, matrix512x512, FOV50cm。 Subsequentlyunderwent PET emission scans,2.5min/bed。PET tomographic images with low-doseCT for attenuation correction and iterative reconstruction，PET and CT images istransferred to the AW workstation fusion display frame on the bit of the frame image。WB-DWI use GE Signa HDx1.5T MRI scanning system，Scan parameters： TR4300ms，TE69.6ms TI160ms， matrix128×128， NEX6FOV40cm x40cm，thickness7mm，pitch1mm， b is800。In accordance with the individual’s height andweight in4-5paragraphs acquisition，an acquisition of39floors，each segmentacquisition time of about300s。After axial acquisition，will be dispersed the originalimage successive sum，each39layers，2layer overlap between paragraphs。The AWworkstation line3D-MIP reconstruction and black-and-white flip technology shows theobserved image。WB-DWI exclude abnormal high signal in the normal structure of thehigh signal other than the primary tumor relative to the background suspicious lesions，combined with the cross section of the original image， the positioning of thethree-dimensional rotation and multi-planar reconstruction images of suspiciouslesions，combined with b=0，the corresponding T2image for diagnosis。Statistics of two methods of benign and malignant tumors in the diagnosis andstaging of malignant tumors， each detection of metastatic lymph nodes and distantmetastases number of lesions，and calculated the diagnostic accuracy of WB-DWI。Dataobtained using the SPSS17.0statistical software for analysis，P <0.05was consideredstatistically significant。Results: WB-DWI and PET/CT in the diagnosis of benign and malignantlesions， and T stage relatively consistent。PET/CT found primary and metastaticlesions in141， WB-DWI found137。PET/CT found54lymph node metastases，and45distant metastases；59lymph node metastases and36distant metastases were foundin WB-DWI。WB-DWI diagnostic accuracy of lymph node metastases was89.8%（53/59）；diagnosis of distant metastases accuracy rate was94.4%（34/36）。For the casesby WB-DWI，the sensitivity of N staging is95.7%，specificity is78.9%，a false positiverate of21.1%and a false negative rate of4.3%； M staging sensitivity84.6%，specificity93.1%，the false-positive rate of6.9%， the false-negative rate of15.4%。 The difference of two methods on the N and M staging system was not significant （P>0.05）。There is a excellent consistency between WB-DWI and PET/CT in N staging，high consistency in M staging。Conclusion: WB-DWI in qualitative and T staging with PET/CT compared to nodifference，but the image quality and quantitative analysis ability aren’t as good asPET/CT，PET/CT can show the lesion size、 shape、 density and the invasion ofadjacent tissue degree。In N and M staging， WB-DWI’s limitations to thegeneration of false-positive and false-negative，WB-DWI and PET/CT in the diagnosisand staging of benign and malignant tumors， there is still some gaps， PET/CT scancould not replaced completely。Certain pathological type of tumor sensitivity of¹⁸F-FDG is poor，when the clinical suspicion is these types of SUVmax value is notsignificantly increased but abnormal anatomy of the lesions combined with CT imagesfor further diagnosis，scan delay necessary。...