The diagnostic value of intravoxel incoherent motion diffusion-weighted imaging for distinguishing nonhypervascular pancreatic neuroendocrine tumors from pancreatic ductal adenocarcinomas
“…20 Intravoxel incoherent motion (IVIM) diffusion-weighted MRI is another research path for characterization of pancreatic tumors, with perfusion fraction ( f ) being a discriminating variable to differentiate PDAC from auto-immune pancreatitis (AIP) and from non-hypervascular pancreatic neuroendocrine tumors. 21,22 IVIM can also be used to differentiate between poorly differentiated PDAC from well/moderately differentiated PDAC. 23 Figure 1.65-year-old woman with pancreatic ductal adenocarcinoma of the pancreatic head.…”
Pancreatic ductal carcinoma (PDAC) is one of the leading causes of cancer-related death worldwide. Computed tomography (CT) remains the primary imaging modality for diagnosis of PDAC. However, CT has limitations for early pancreatic tumor detection and tumor characterization so that it is currently challenged by magnetic resonance imaging. More recently, a particular attention has been given to radiomics for the characterization of pancreatic lesions using extraction and analysis of quantitative imaging features. In addition, radiomics has currently many applications that are developed in conjunction with artificial intelligence (AI) with the aim of better characterizing pancreatic lesions and providing a more precise assessment of tumor burden. This review article sums up recent advances in imaging of PDAC in the field of image/data acquisition, tumor detection, tumor characterization, treatment response evaluation, and preoperative planning. In addition, current applications of radiomics and AI in the field of PDAC are discussed.
“…20 Intravoxel incoherent motion (IVIM) diffusion-weighted MRI is another research path for characterization of pancreatic tumors, with perfusion fraction ( f ) being a discriminating variable to differentiate PDAC from auto-immune pancreatitis (AIP) and from non-hypervascular pancreatic neuroendocrine tumors. 21,22 IVIM can also be used to differentiate between poorly differentiated PDAC from well/moderately differentiated PDAC. 23 Figure 1.65-year-old woman with pancreatic ductal adenocarcinoma of the pancreatic head.…”
Pancreatic ductal carcinoma (PDAC) is one of the leading causes of cancer-related death worldwide. Computed tomography (CT) remains the primary imaging modality for diagnosis of PDAC. However, CT has limitations for early pancreatic tumor detection and tumor characterization so that it is currently challenged by magnetic resonance imaging. More recently, a particular attention has been given to radiomics for the characterization of pancreatic lesions using extraction and analysis of quantitative imaging features. In addition, radiomics has currently many applications that are developed in conjunction with artificial intelligence (AI) with the aim of better characterizing pancreatic lesions and providing a more precise assessment of tumor burden. This review article sums up recent advances in imaging of PDAC in the field of image/data acquisition, tumor detection, tumor characterization, treatment response evaluation, and preoperative planning. In addition, current applications of radiomics and AI in the field of PDAC are discussed.
“…Magnetic resonance imaging with MRCP is also useful for objective visualization of the pancreatic duct and cysts, although the present results indicate that MRI/MRCP is less sensitive to EUS in terms of detecting early CP-like appearance, which may be improved by applying 3.0 T MRI. The indirect findings, such as ductal disruption, following dilated distal MPD and nearby pancreatic cyst were clearly detected by MRCP ( Figure 4D ) although the pancreatic mass was not detected even with DWI, which may be improved by a different sequence, such as DWI, with advanced post-processing and motion correction or intravoxel incoherent motion DWI ( 22 , 23 ). Nevertheless, MRI/MRCP is a useful complementary imaging tool for PC screening that can detect small pancreatic cysts in the pancreatic tail or uncinate, which can be difficult to visualize by radial EUS.…”
Background and AimsAttention is increasingly being paid to family history of pancreatic cancer (PC) as a risk factor for developing PC. It is mandatory to develop a screening system for early detection of PC; however, the relationship between a family history of PC and the incidence of pancreatic abnormalities, such as pancreatic cyst and chronic pancreatitis (CP), in the Japanese population remains unknown.Patients and MethodsIndividuals with a family history of PC were prospectively enrolled in a screening program using forward-viewing radial endoscopic ultrasound (FR-EUS) and magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) as the diagnostic modalities.ResultsIn total, forty-three individuals in 37 families were enrolled (mean age, 54 years). All individuals underwent FR-EUS and MRI with no complications. FR-EUS revealed resectable PC (n = 1, 2.3%), pancreatic cysts (n = 24, 55.8%), intraductal papillary mucinous neoplasm (IPMN; n = 13, 30.2%), and early CP-like appearance (n = 15, 34.9%). The detection rate of early CP-like appearance was significantly higher by EUS than by MRI. Pancreatic cysts and IPMN detected by FR-EUS were significantly correlated to age (≥60 years) and less correlated to men (hazard ratio [HR] 22.4; 95% confidence interval [CI], 2.10–236.0; p < 0.01 and HR 0.092; 95% CI, 0.01–0.83; p = 0.033, respectively). Early CP-like appearance detected by FR-EUS was significantly correlated with men and smoking (HR 5.0; 95% CI, 1.3–19.3; p = 0.02 and HR 4.02; 95% CI, 0.991–16.3; p = 0.05, respectively).ConclusionA screening system using FR-EUS and MRI/MRCP for individuals with a family history of PC was useful for identifying curable PC and pancreatic abnormalities. The incidence of pancreatic cysts, such as IPMN and early CP-like appearance, was also high in the Japanese cohort.
“…Zeng et al showed that conventional DWI and IVIM models are valuable tools to differentiate nonhypervascular PNETs from PDACs. D* showed better performance than f and ADC [ 141 ]. Improvements in scanner performance and the optimization of pulse sequences have reduced acquisition times and increased the use of whole-body MRI (WB-MRI) in several clinical scenarios [ 142 ].…”
Section: Diagnosis Staging and Risk Assessmentmentioning
Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) comprise a heterogeneous group of neoplasms, which derive from cells of the diffuse neuroendocrine system that specializes in producing hormones and neuropeptides and arise in most cases sporadically and, to a lesser extent, in the context of complex genetic syndromes. Furthermore, they are primarily nonfunctioning, while, in the case of insulinomas, gastrinomas, glucagonomas, vipomas, and somatostatinomas, they produce hormones responsible for clinical syndromes. The GEP-NEN tumor grade and cell differentiation may result in different clinical behaviors and prognoses, with grade one (G1) and grade two (G2) neuroendocrine tumors showing a more favorable outcome than grade three (G3) NET and neuroendocrine carcinoma. Two critical issues should be considered in the NEN diagnostic workup: first, the need to identify the presence of the tumor, and, second, to define the primary site and evaluate regional and distant metastases. Indeed, the primary site, stage, grade, and function are prognostic factors that the radiologist should evaluate to guide prognosis and management. The correct diagnostic management of the patient includes a combination of morphological and functional evaluations. Concerning morphological evaluations, according to the consensus guidelines of the European Neuroendocrine Tumor Society (ENETS), computed tomography (CT) with a contrast medium is recommended. Contrast-enhanced magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI), is usually indicated for use to evaluate the liver, pancreas, brain, and bones. Ultrasonography (US) is often helpful in the initial diagnosis of liver metastases, and contrast-enhanced ultrasound (CEUS) can solve problems in characterizing the liver, as this tool can guide the biopsy of liver lesions. In addition, intraoperative ultrasound is an effective tool during surgical procedures. Positron emission tomography (PET-CT) with FDG for nonfunctioning lesions and somatostatin analogs for functional lesions are very useful for identifying and evaluating metabolic receptors. The detection of heterogeneity in somatostatin receptor (SSTR) expression is also crucial for treatment decision making. In this narrative review, we have described the role of morphological and functional imaging tools in the assessment of GEP-NENs according to current major guidelines.
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