3.0T MRI Sequences Compare And Value Of Diffusion-weighted Imaging In Advanced Gastric Cancer

Objective To analysis image quality of three kinds T2WI sequences（FRFSE、FS-FSE、SSFSE）and two kinds T1WI sequences （SPGR-dual echo、LAVA）, andcompare T-staging accuracy in gastric cancer of different sequences， in order toevaluation the value of each sequence in3.0T MRI imaging of gastric cance.Methods Confirmed by endoscopy and pathology of gastric cancer in29patients withpreoperative MRI examination. Twenty-first cases of gastric cancer were undergone with thethree kinds T2WI sequence, analysis image quality and comparison of those sequences SNR（signal to noise ratio） and CNR（contrast to noise ratio）; Twenty-nine cases of gastriccancer were undergone with the T2WI sequence and two kinds T1WI sequence, comparison ofthose sequences image quality and T-stage accuracy, analysis value of gastric cancer in MRIexamination.Results1.The SNR and CNR were significantly different in three kinds T2WIsequences. FRFSE and SSFSE sequence of SNR and CNR was significantly higher theFS-FSE sequence, the difference was statistically significant (P=0.00)；FRFSE and SSFSEsequence of SNR and CNR was no statistically significant (P>0.05)；The image qualitygrading were satistically significant, FRFSE and SSFSE sequence was better than the FS-FSE sequences.2. There were significant difference in image quality score in T2WI sequences and twokinds T1WI sequences. The LAVA sequence shown in tumor and adjacent organs, and artifacts score better than the other sequences; LAVA sequence T-staging accuracyof up to82.8%, T2WI sequence lowest of48.3%, three sequences combination of analysisT-staging correctness up to93.1%. T2WI and SPGR-dual echo sequence on T-staging falsepositives in the high contracting a higher proportion of37.9%and24.1%.Conclusion1. Before the examination of gastric cancer patients in3.0T MRI, withhypotonic, moderate stomach cavity filling, as well as patient and meticulous respiratorytraining are prerequisites to obtain high quality MRI images of gastric cancer.2.3.0T MRI for gastric cancer check, T2WI sequence shows the gastric wall layeringstructure and can identify lesions of the internal organization of ingredients, therefore it isthe basic imaging sequence for MRI examination of gastric cancer.When we use water asthe contrast agent in the gastric lumen, FRFSE sequence is preferred. But often producemore serious artifacts, SSFSE as an important complementary sequence; fat-suppressedfast spin-echo (FS-of FSE) sequence is not used for the evaluation of T-staging of gastriccancer, it might be the identification of lymph node metastasis as well as used in theidentification of liver tumors,it can also be used as a complementary sequence.3. SPGR-dual echo sequence is helpful to Diagnosis gastric cancer T-staging. TheLAVA sequence of image quality is better, T-staging the highest diagnostic accuracy, To acertain extent, LAVA sequence reflect the pathological features and its blood supply, thevalue is important. Both of them are the basical3.0T MRI imaging sequence of gastriccancer, in inspection should be mutually complementary. Objective To analysis of3.0T magnetic resonance gastric cancer between singlebreath-hold and separate breath holds with diffusion-weighted imaging in gastric cancer,compare gastric cancer with normal gastric wall, transfer and non-metastatic lymph nodesbetween the ADC value differences。To explore the application value of the sequence inadvanced gastric cancer.Methods29Patients with gastric cancer were confirmed by endoscopy andpathology，with MRI diffusion-weighted imaging (DWI) examination brfore the surgery.Scand two times with single breath-hold and separate breath holds in18patients，comparingtwo examination methods between the signal to noise ratio and contrast to noise ratio, theapparent diffusion coefficient (ADC value), as well as all29cases of patients with gastriccancerdifference between the ADC values with the normal gastric wall; And transfernon-metastatic lymph nodes between the ADC value differences preliminary comparison,then explore the value of the sequence in the diagnosis of gastric cancer before surgery.Results1. In3.0T diffusion-weighted imaging, cancer district are manifested as avisible high signal, significant signal difference with the normal gastric wall. Normal gastricand tumor ADC measurement differences between the two methods was no statisticallysignificant (P>0.05), The single breath-hold DWI imaging signal to noise ratio, contrast tonoise was significantly higher than separate breath holds scan, a single breath stomach cavityfree water, and the background noise signal intensity was significantly lower than theseparate breath holds scan, the differences were statistically significant (P=0.00), DWI images of Single breathe holds scan in breathing movement and ASSET artifacts aresignificantly reduced. ADC value of gastric cancer compared with normal gastric ADC valuedifference was statistically significant （t=10.17, P=0.00）, gastric cancer group wassignificantly lower than normal ADC values of the stomach wall group.2. Preliminary comparison of metastasis to lymph node ADC value differences betweentransfer and non-significant difference （t=6.23, P=0.00）, lymph node metastasis ADCvalue was significantly lower than non-metastatic lymph nodes ADC value.Conclusion Diffusion weighted imaging in a single breath-hold image quality wassuperior to separate breath holds scan of3.0T magnetic resonance gastric cancer, gastriccancer ADC value was significantly lower than the normal gastric wall ADC value ofmetastatic lymph nodes ADC values were significantly lower than non-metastatic lymphnodes ADC value. DWI imaging combined with fat-suppressed T2WI might be a larger shiftand hyperplasia of lymph nodes to make a meaningful differential diagnosis should be usedas a regular sequence.