|ECR 2013 / C-1474|
|Imaging and pathological findings of solid pseudopapillary tumor of the pancreas: a report of 53 cases|
Methods and Materials
- We reviewed a series of 53 cases in our hospital between Jan 2005 and Feb 2012.
- Patients with histopathologic confirmed SPTs who had undergone material-enhanced CT or MRI prior to surgery were included.These included 5 male and 48 female (mean age: 33 years; age range, 13-68 years). 21 of 48 female were younger than 30 years old.
- The pathologic results were conducted under the 2000th edition World Health Organization(WHO) Classification of Tumors which defined SPTs with specific vessels and nerves invasion, invasion to adjacent pancreatic parenchyma or organs, lymph nodes involvement and metastasis as solid pseudopapillary carcinoma (SPC) of the pancreas.
- 44 patients were performed CT by using the following CT scanners: Toshiba Aquillion 64-MDCT scanner(n=30), Light Speed 64-channel CT scanner(n=14). They underwent upper-abdomen routine scan after drinking 800~1000ml warm water. A bolus of nonionic contrast agent (Ultravist 300ml I/L) was used as the contrast material for dynamic contrast-enhanced CT images, administered as an IV infusion, injected at a rate of 3~3.5 mL/s and at a dose of 1.5ml/kg body weight.
- Dynamic CT images were obtained 25s, 45s and 65s respectively after completion of the intravenous injection, corresponding to arterial phase, pancreatic phase and portal phase. Images with 5mm-thick sections were acquired and reconstruction was performed with the thickness of 1.25mm and reconstruction interval of 0.8 mm for both scanners.
- 21 patients were performed MRI after fasting for 6-8 hours. All images were performed using a 3.0 T superconduction MR scanner and phased array body coils for MRI multi-sequence scan, including T1-FSE (Fast spin echo)sequence（TR：300ms，TE：3.9ms）,T2-FSEsequence（TR：6667ms，TE：117ms ）,T2-FSE sequence with fat suppression （TR：6667ms， TE：103ms). Images of axial plane were collected and the scan range is from the superior border of liver to the inferior border of the kidney.
- 18 dynamic contrast-enhanced MR images were acquired in the axial plane using a T1-weighted in-phase two-dimensional gradient-echo MR sequence (TR, 2.8ms; TE, 1.3 ms; slice thickness, 3.8mm with 0 mm interslice gap; breathholding, 17-22s). A bolus of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) was administered to all patients as the intravenous contrast material; the Gd-DTPA dose was 0.1mmol per kilogram of body weight at an intravenously injection rate of 2.0ml/s. Arterial phase MR images were obtained 15s after completion of the intravenous infusion. The operation was repeated for 3 times with a 5s internal and it was achieved with portal phase and delay phase for 50s and 110s after Gd-DTPA administration successively.
All CT and MRI images were analyzed by two certified radiologist The images were read simultaneously by both readers and a consensus was reached.
- Review: location, morphology, size, capsule, margin, calcification, hemorrhage, constitution, attenuation/intensity, enhancing model, dilation of pancreatic and biliary ducts, invasion to adjacent organs, lymphadenopathy et al.
- solid-to-cystic component ratio: purely solid, mixed with more than 50% of tumor with solid component, mixed with less than 50% of tumor with solid component and purely cystic.
- the enhancement pattern during pancreatic phase:homogeneous, heterogeneous, peripheral enhancement and minimal enhancement.
- tumor size (maximal diameter): Small group was 3 cm or less in diameter, middle group was between 3 and 6 cm (include 6) and large SPTs were greater than 6cm.
- age groups (30 years old or younger and over 30 years old),
- gender groups (male and female)
- benign SPTs and SPCs.
- Quantitative variables: were shown as means±standard deviations.
- Classified variables: were shown as counts and percentages.
- Mann-Whitney test: to compare age and diameters between different groups.
- The Fisher exact test or chi-square test:to evaluate differences of categorical variables among groups.
P<.05 was considered to be significantly different. The Statistical analysis was performed by using SPSS for Windows, version 17.0,2008.
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