Evaluation of the preoperative staging of rectal cancer by magnetic resonance imaging / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To evaluate the value of MRI in preoperative staging of rectal cancer.</p><p><b>METHODS</b>The data of 156 rectal cancer patients,undergone MRI scans from December 2004 to June 2006 in our hospital, were analyzed retrospectively. Findings of MRI were compared with postoperative pathological examinations.</p><p><b>RESULTS</b>Intracavitary localized parenchyma tumors were seen in 72 cases, and intestinal wall abnormal incrassation or stricture in other 84 cases from MRI scan. Sixteen cases had rectal polyps simultaneously, 2 cases ovarian cysts, 13 cases anterior-sacral metastases and 2 cases bone metastases. The sensitivity and specificity of T(1-2), T(3) and T(4) rectal cancer by MRI examination were 25%(8/32), 93.3%(84/90), 94.1%(32/34) and 100%(124/124), 57.6%(38/66), 96.7%(118/122) respectively. In MRI imaging, metastatic para-rectal lymph node was diagnosed as the diameter >5 mm or abnormal border or mixed resonance, with a sensitivity of 85.1%(80/94) and specificity of 45.2%(28/62).</p><p><b>CONCLUSION</b>MRI has high accuracy for preoperative staging of rectal cancer, and is useful to detect the serosal infiltration and lymph node metastasis.</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>

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>

Value of multidetector computed tomography in differentiating ovarian tumors from non-ovarian masses / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the ability of multidetector computed tomography (MDCT) in differentiating ovarian tumors from non-ovarian masses.</p><p><b>METHODS</b>Forty-two cases with pelvic masses were examined with 16-row MDCT. All source image of each case was put into workstation for multi-planar reconstruction (MPR) and curved planar reconstruction(CPR). Axial image combined with 2D image was used for determining the relationship of the mass to ovarian vascular pedicle and identifying the normal ovary, which was compared with postoperative pathologic result and the finding during operation. All the data was compared using Fisher's exact test.</p><p><b>RESULTS</b>There were 28 ovarian tumors and 14 non-ovarian tumors in this series. If the ovarian vascular pedicle sign was used for determining whether the tumor was from the ovary or not, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy was 89.3%, 85.7%, 92.6%, 80.0% and 88.1%, respectively, with a significant difference in differentiating the tumor from the ovary or non-ovarian organs (P <0.05). If the identification of full normal ovary was used to determine non-ovarian origin of the tumor, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy was 50.0%, 100.0%, 100.0%, 80.0% and 83.3%, respectively, also with a significant difference in differentiating the tumors from the ovary or non-ovarian organs (P <0.05).</p><p><b>CONCLUSION</b>MDCT can clearly show the relationship of the tumor to the normal ovary and its vascular pedicle, which is very helpful in differentiating the ovarian tumors from a non-ovarian masses.</p>

CT diagnosis of intraductal papillary mucinous tumor of the pancreas / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the CT and MRI manifestatitions of intraductal papillary mucinous neoplasm (IPMN) of the pancreas.</p><p><b>METHODS</b>Both clinical and imaging data of 12 pathologically confirmed intraductal papillary mucinous neoplasm, of the pancreas were retrospectively analyzed.</p><p><b>RESULTS</b>The pancreatic IPMN can be classified into two types based on CT image: the branch duct IPMN (n=7) originated from the head and uncinate process of the pancreas. The tumor consisted of lobulated or clustered small cyst lesions with septa among them, the wall and septa can be enhanced; the combined IPMN (n=5) involved branch ducts of the uncinate process as well as the main pancreatic ducts with dilatation (diameter: 4-7 mm), one of these involved the branch ducts along the pancreatic body. The pancreatic IPMN was mainly found in elderly patient with a chief clinical symptoms of abdominal pain and/or pancreatitis.</p><p><b>CONCLUSION</b>The intraductal papillary mucinous neoplasm of the pancreas enjoys specific features in CT and MRI image, which are helpful to the diagnosis.</p>