Comparison of MRI manifestations and histopathologic findings in pancreatic head carcinoma in vivo ex vivo / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To prospectively analyze the correlation of MRI image characteristics with histopathological findings in pancreatic head carcinoma in vivo and ex vivo.</p><p><b>METHODS</b>Sixteen patients with pancreatic head carcinoma were examined by 1.5T MRI. MR sequences included pre-and post-contrast dynamic 2D FLASH T1WI, TSE T2WI + fat suppressed (FS). All fresh specimens were scanned again within an hour after resection during the Whipple procedure, and were then cut into slices along the direction of MRI scan. The MRI image characteristics were compared with gross and histopathologic findings of the specimens.</p><p><b>RESULTS</b>The tumor size ranged from 1.5 cm x 2.0 cm to 4.8 cm x 4.2 cm with a mean value of 3.6 cm x 3.1 cm. The MRI findings in vivo showed hypointensity in 14 lesions and isointensity in 2, and on 2D FLASH T1WI and TSE T2WI, all lesions displayed mixed intensity except 3 lesions with iso-intensity. During post-contrast dynamic pancreatic parenchymal phase, 15 lesions showed mild enhancement and 11 lesions had ring enhancement sign. Nine lesions displayed progressive irregular moderate enhancement during post-contrast dynamic hepatic phase. Four lesions showed enhancement with iso- and hyperintensity in post-contrast dynamic delayed phase. The MRI findings demonstrated that all lesions ex vivo had hypointensity on 2D FLASH T1 WI and mixed intensity on TSE T2WI + FS. Tumor tissues mainly displayed hypointensity, and the area containing tumor and inflammatory tissue showed iso-intensity on 2D FLASH T1WI. On T2WI + FS, the fibrosis proportion displayed hypo or isointensity, while the tumor and chronic inflammatory tissue demonstrated slight hyperintensity, and the zones of mucous degeneration or pancreatic ductal dilatation displayed hyper-intensity. The ring enhancement of tumor was caused by multiple factors and no obvious enhancement within tumor and fibrosis area were observed during post-contrast dynamic pancreatic parenchymal phase. Progressive irregular enhancement originated from desmoplastic reaction within the tumor during post-contrast dynamic hepatic phase and delayed phase, respectively.</p><p><b>CONCLUSION</b>Pancreatic head carcinomas contain various kinds of tissues. MRI can reveal these pathologic characteristics. No obvious hemorrhage and necrosis within the tumor were observed in this series.</p>

MRI in the evaluation of peripancreatic vessel invasion and resectability of pancreatic carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the role of MRI in evaluating the peripancreatic vessel invasion and resectability of pancreatic carcinoma based on the comparison of MRI image with surgical exploration, and try to establish the criteria for assessment of the sensitivity, specificity and accuracy of resectability.</p><p><b>METHODS</b>Forty-one pancreatic carcinoma patients confirmed by pathology received preoperative plain and contrast enhanced MRI scan, and 37 of them had additional coronal MRA scan. Peripancreatic vessel invasion was preoperatively assessed based on MRI features, and the vessel invasion degree from the uninvolved to the severely involved was divided into 6 grades represented by 1, 2a, 2b, 3a, 3b and 4, respectively. Compared with the findings during the surgery, the sensitivity and specificity of each vessel invasion grade were studied and the receiver operator characteristic curve (ROC) was drawn. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of resectability evaluation based on 2 and 2a degree were calculated respectively. The resectability of involved arteries and veins of grade 2 were also analyzed.</p><p><b>RESULTS</b>Of the 41 patients, 22 had resectable tumor, with 20 curative resection and 2 palliative. Compared with the findings during surgery, seven vessels including three arteries and four veins were not correctly interpreted by MRI. If grade 1,2a,2b,3a and 3b was used as the resectable standard,respectively, the sensitivity to predict the unresectbility was 78.3%, 84.8%, 67.4%, 56.5% and 47.8%, respectively. Receiver operator characteristic curve demonstrated that grade 2a was the optimal critical point. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of grade 2a in predicting the unresectbility were 84.8%, 98.5%, 92.9%, 96.6% and 95.9%.</p><p><b>CONCLUSION</b>Our data showed that grade 2a (tumor involvement < 2 cm long and < 1/2 circumference of the vessel) may be more sensitive and accurate in predicting the resectability, which may be considered as the line of demarcation between the respectable and unresectable cases in clinical practice.</p>

Evaluation of 2D and 3D MRI imaging in the diagnosis of pancreatic carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate various kinds of sequences and modified dynamic contrast-enhanced MRI methods in the diagnosis of pancreatic carcinoma.</p><p><b>METHODS</b>Forty-nine pancreatic carcinoma patients proved by histopathology or clinical examination and follow-up underwent MR examination. Plain MR sequences included: T1-weighted 2D FLASH, T1 WI 3D VIBE, TSE T2 WI and HASTE with FS. Modified dynamic contrast-enhanced scanning procedures were coronal scaning with 3D FLASH and axial scaning using T1 WI 3D VIBE sequences in turn for the upper abdominal area and pancreatic area. The coronal imaging were used to obtain 3D peripancreatic vessels during arterial phase and portal vein phase scanning, respectively. The axial imaging were used to detect the tumor in pancreatic parenchymal phase and delayed phase scanning, respectively. Final scanning for the whole upper abdomen was performed using T1 WI 2D FLASH axial sequence.</p><p><b>RESULTS</b>(1) Of 49 lesions in these patients, 45 showed hypo-intensity and 4 iso-intensity on 3D VIBE. Forty-six lesions showed hypo-intensity and 3 isointensity on 2D FLASH. On TSE T2 + FS, lesion contour was not clear enough; 3 of them displayed isointensity, the other showed iso- or hyper-intensity. (2) During pancreatic parenchymal phase, 48 lesions showed hypo-intensity and 39 ring enhancement. Twenty-four lesions displayed marginal tubercle and inner compartment enhancement during portal vein and delayed phase. Six lesions showed iso- or hyper-intensity in delayed phase. (3) Thirty-seven patients underwent surgical exploration. MRI and MRA had a good correlation with surgical findings for peripancreatic vessels which were diagnosed as being invasive or noninvasive by tumors except three superior mesenteric arteries and four superior mesenteric veins being misdiagnosed.</p><p><b>CONCLUSION</b>As"one-stop-shop" MRI examination, modified MRI sequences consisting of dynamic coronal and axial contrast-enhanced scanning is feasible and helpful in diagnosing, staging and assessing the resectability for pancreatic carcinoma.</p>

The comparative study of diffusion-weighted MR imaging with modified sensitivity encoding technique for small hepatocellular carcinoma lesions / 中华放射学杂志

Objective To prospectively evaluate whether DWI with mSENSE(mSENSE-DW1)can help to improve image quality and affect the calculation of lesion's ADC,compared with DWI with conventional phase encoding(conventional DWI)in patients with small HCC lesions.Methods Thirty-two patients with 47 small HCC lesions underwent single-shot spin-echo echo-planar.(SE-EPI)DWI with conventional phase encoding and mSENSE.Three b values of 300,500 and 800 s/mm~2 were used.Image quality and CNR between conventional DWI and mSENSE-DWI group were compared with different b value. Lesion's ADC were also calculated and compared.Matched-pairs Wilcoxon signed rank test and Friedman test were used to test statistical significance.Results The image quality was assessed with a five-point scale.For conventional DWI group,image quality score of 2 was assigned in 5 cases,score of 3 in 24 cases, score of 4 in remaining 3 eases with b=300 s/mm~2,score of 2 in 9 eases,score of 3 in 22 cases,score of 4 in remainingl cases with b=500 s/mm~2,score of 1 in 2 cases,score of 2 in 24 cases,score of 3 in remaining 6 cases with b=800 s/mm~2.For mSENSE-DWI group,image quality score of 3 was assigned in 4 cases,score of 4 in 25 cases,score of 5 in 3 eases with b=300 s/mm~2,score of 3 in 10 cases,score of 4 in 20 cases,score of 5 in remaining 2 cases with b=500 s/mm~2,score of 2 in 7 cases,score of 3 in 23 eases, score of 4 in remaining 2 cases with b=800 s/mm~2.Higher image quality scores were achieved at mSENSE- DWI group than conventional DWI group(Z=-5.578,-5.488,-4.796 respectively,P