Is the combination of MR and CT findings useful in determining the tumor grade of pancreatic neuroendocrine tumors?
- 427 Downloads
To retrospectively elucidate the findings useful in determining the tumor grade of pancreatic neuroendocrine tumors (PNETs) by combined assessment of magnetic resonance (MR) and dynamic computed tomography (CT) images.
Materials and methods
Eighty-nine patients with PNETs (96 lesions) were included, and classified as G1, 59; G2, 29; and G3, 8 lesions. Image analysis included lesion diameter, shape, enhancement pattern on arterial phase (AP) and delayed phase CT images, calcification, cystic portion, main pancreatic duct dilatation, signal-intensity on T1-, T2-weighted MR images, and appearance of apparent diffusion coefficient (ADC).
Significant differences among G1, G2, and G3 groups were noted in tumor maximal diameter (p < 0.0001), shape (p < 0.0001), enhancement pattern on AP image (p < 0.0001), cystic portion (p = 0.012), and ADC finding. In multivariate analysis, ADC finding was the independent factor (p = 0.002). The combination findings of low ADC ratio (ADC value of the lesion/ADC value of the parenchyma <0.94), not homogeneous hyper-attenuation, lobulated shape, and hyper-intensity on T2-weighted image were suggestive of G2 or G3 with a probability of 100%. Conversely, all lesions with high ADC ratio and small size (≤25 mm) belonged to the G1 group.
Combined assessment of MR and CT findings could improve the prediction of tumor grading in PNETs.
KeywordsPancreatic neuroendocrine tumors Neuroendocrine tumors G1 Neuroendocrine tumors G2 Neuroendocrine carcinoma Magnetic resonance imaging (MRI) Computed tomography (CT)
The authors state that this work has not received any funding.
Conflict of interest
The authors declare no conflict of interest associated with this manuscript.
- 1.Hruban RH, Pitman MB, Klimstra DS. Tumors of the pancreas. AFIP atlas of tumor pathology. 4th series fascicle 6. Washington: American Registry of Pathology; 2007.Google Scholar
- 3.Klimstra DS, Arnold R, Capella, et al. Neuroendocrine neoplasms of the pancreas. In: Bosman F, Carneiro F, Hruban RH, Theise ND, editors. WHO classification of tumours of the digestive system. 4th ed. Lyon: IARC Press; 2010. p. 322–6.Google Scholar
- 28.National Comprehensive Cancer Network. NCCN clinical practice guidelines in oncology. Neuroendocrine tumors 2015 version 1. [National Comprehensive Cancer Network Web site]. http://www.nccn.org/. Accessed 30 Jan 2015.