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Ectopic pancreas in upper gastrointestinal tract: MRI findings with emphasis on differentiation from submucosal tumor
Kyung Mi Jang1, Seong Hyun Kim, Hyun Jeong Park
1Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Background:
Ectopic pancreas can frequently be mistaken for other submucosal masses. Ectopic pancreas may follow the signal intensity of mother pancreas on various magnetic resonance (MR) sequences, which might be helpful for differentiation between ectopic pancreas and other submucosal tumors in upper gastrointestinal (UGI) tract.
Purpose:
To evaluate the value of MR imaging (MRI) in differentiating ectopic pancreases from submucosal tumors in UGI tract.
Material And Methods:
Fifteen patients with ectopic pancreas and 26 patients with UGI submucosal tumors were included. All patients underwent abdominal MRI with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced MRI. Qualitative (location, contour, growth pattern, lesion border, and presence of intralesional cystic portion and duct-like structure) and quantitative (long diameter [LD], short diameter [SD], LD/SD ratio, signal intensities and apparent diffusion coefficients [ADC], and signal intensity - and ADC ratios of UGI submucosal lesions to pancreas) parameters were compared between ectopic pancreases and UGI submucosal tumors using Fisher's exact test, the Mann-Whitney U test, and receiver-operating characteristic (ROC) analysis.
Results:
Duodenum was the most common location for ectopic pancreas (12/15, 79.9%), and the gastric body for UGI submucosal tumors (15/26, 57.7%) (P = 0.005). Round shape was an imaging feature more common in UGI submucosal tumors (12/26, 46.2%) than in ectopic pancreas (1/15, 6.7%; P = 0.021). On all of the various pulse sequences of MR images, ectopic pancreas showed isointensity comparable to that of pancreas more frequently than did sequences of UGI submucosal tumors (P < 0.01).The means (0.95 ± 0.09, 0.99 ± 0.06, 1.07 ± 0.08) of the signal intensity ratio of ectopic pancreas to pancreas on fat-suppressed unenhanced T1-weighted, arterial, and portal phase images were significantly higher than those (0.60 ± 0.09, 0.62 ± 0.28, 0.86 ± 0.27) of UGI submucosal tumors (P < 0.05). In contrast, the means (1.05 ± 0.12, 0.93 ± 0.18) of the signal intensity ratios of ectopic pancreas on T2-weighted images and DW images (b = 800 s/mm(2)) were significantly lower than those (1.82 ± 0.39, 2.35 ± 0.94) of UGI submucosal tumors (P < 0.001). On ROC analysis, if absolute value of difference between 1.0 and signal intensity ratio of submucosal lesions to the pancreas on T1-weighted images is <0.21, the sensitivity and specificity reach 100.0% for diagnosis ectopic pancreas from submucosal tumors.
Conclusion:
Abdominal MRI with DWI can be a valuable tool for differentiating ectopic pancreases from UGI submucosal tumors.
Insights
Magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) helps differentiate ectopic pancreas from upper gastrointestinal (UGI) submucosal tumors. This advanced MRI technique offers high accuracy in distinguishing these conditions, improving diagnostic confidence.
Area of Science:
- Gastroenterology
- Radiology
- Medical Imaging
Background:
- Ectopic pancreas is often misdiagnosed as other submucosal masses.
- Ectopic pancreas may exhibit signal intensities similar to the native pancreas on MRI, aiding differentiation.
Purpose of the Study:
- To assess the utility of MRI in distinguishing ectopic pancreas from upper gastrointestinal (UGI) submucosal tumors.
Main Methods:
- Compared MRI findings (qualitative and quantitative parameters) in 15 ectopic pancreas patients and 26 UGI submucosal tumor patients.
- Utilized diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced MRI.
- Employed statistical analyses including Fisher's exact test, Mann-Whitney U test, and ROC analysis.
Main Results:
- Ectopic pancreas most commonly located in the duodenum (79.9%), while UGI submucosal tumors were frequent in the gastric body (57.7%).
- Ectopic pancreas showed isointensity with the native pancreas on most MRI sequences, unlike submucosal tumors.
- Specific signal intensity ratios on T1-weighted, T2-weighted, and DWI sequences, along with ROC analysis, demonstrated high diagnostic accuracy.
Conclusions:
- Abdominal MRI, particularly with DWI, is a valuable tool for differentiating ectopic pancreas from UGI submucosal tumors.
- MRI parameters provide reliable criteria for distinguishing these entities, aiding clinical management.
