Pancreatic neuroendocrine tumor: Added value of fusion of T2-weighted imaging and high b-value diffusion-weighted imaging for tumor detection (original) (raw)
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Objectives: The aims of this study were to investigate the added value of diffusion-weighted imaging (DWI) in pancreatic neuroendocrine tumor (pNET) evaluation and to compare magnetic resonance imaging (MRI) to 68 Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) results. Methods: Morphological MRI (T2-weighted [T2-w] + contrast-enhanced [CE] T1-w) and DWI (T2-w + DWI) and 68 Ga-DOTANOC PET/CT in 25 patients/30 pNETs were retrospectively evaluated. Per-patient and per-lesion detection rates (pDR and lDR, respectively) were calculated. Apparent diffusion coefficient values were compared among pNET and surrounding and normal pancreas (control group, 18 patients). Apparent diffusion coefficient and standardized uptake value (SUV) values were compared among different grading and staging groups. Results: No statistically significant differences in PET/CT and MRI session detection rates were found (morphological MRI and DW-MRI, 88% pDR and 87% lDR; combined evaluation, 92% pDR and 90% lDR; 68 Ga-DOTANOC PET/CT, 88% pDR and 80% lDR). Consensus reading (morphological/DW-MRI + PET/CT) improved pDR and lDR (100%). Apparent diffusion coefficient mean value was significantly lower compared with surrounding and normal parenchyma (P < 0.01). The apparent diffusion coefficient and SUV values of pNETs among different grading and staging groups were not statistically different. Conclusions: Conventional MRI, DW-MRI + T2-w sequences, and 68 Ga-DOTANOC PET/CT can be alternative tools in pNET detection. Diffusion-weighted MRI could be valuable in patients with clinical suspicion but negative conventional imaging findings. However, the consensus reading of the 3 techniques seems the best approach.
Diagnosis of neuroendocrine tumours by retrospective image fusion: is there a benefit?
European Journal of Nuclear Medicine and Molecular Imaging, 2004
This study evaluated the use of image fusion in the preoperative staging of neuroendocrine tumors (NET) of the pancreas and the gastrointestinal tract (GIT). Thirty-eight patients suffering from a metastasized NET with location of the primary in the pancreas (n=15) or the GIT (n=23) were examined by somatostatin receptor scintigraphy (SRS) and computed tomography (CT). Consecutive image registration and fusion were performed using custom-built software integrated in AVS/Express (Advanced Visual Systems, Waltham, MA, USA). Registration was performed by a voxelbased algorithm based on normalized mutual information. Image fusion was feasible in 36/38 patients. A total of 87 foci were assigned to anatomical regions (e.g. gut, pancreas, liver, lymph node or others) by two independent observers in both SRS and SRS/CT fusion images. The assignments used a binary ranking system (1="definite", 0="not definite"). These results were then retrospectively compared to the classification of the foci, based on postoperative histology or clinical follow-up. Imaging by SRS allowed a definite anatomical assignment in 57% (50/87) and 61% (53/87) of all lesions in the case of observers A and B, respectively. Image fusion improved the topographic assignment to 91% (79/87) and to 93% (81/87). The number classified as "definite" by both observers increased from 54% (47/87) to 86% (77/87). The increase in definite assignments was highly significant for both observers (P<0.0001 for each). In the case of foci classified as liver metastases, image fusion allowed improved assignment to the corresponding liver segment from 45% (18/40) to 98% (39/40) and from 58% (23/40) to 100% (40/40) by observers A and B, respectively. Furthermore, the improved assignment of foci classified as lesions by image fusion was relevant for therapy in 7/36 patients (19%). Therefore, the image fusion technique presented herein appears to be a very useful method for clinical routine.
18F-FDG PET/MRI fusion in characterizing pancreatic tumors: comparison to PET/CT
International Journal of Clinical Oncology, 2011
Objective To demonstrate that positron emission tomography (PET)/magnetic resonance imaging (MRI) fusion was feasible in characterizing pancreatic tumors (PTs), comparing MRI and computed tomography (CT) as mapping images for fusion with PET as well as fused PET/MRI and PET/CT. Methods We retrospectively reviewed 47 sets of 18 F-fluorodeoxyglucose ( 18 F -FDG) PET/CT and MRI examinations to evaluate suspected or known pancreatic cancer. To assess the ability of mapping images for fusion with PET, CT (of PET/CT), T1-and T2-weighted (w) MR images (all noncontrast) were graded regarding the visibility of PT (5-point confidence scale). Fused PET/CT, PET/T1-w or T2-w MR images of the upper abdomen were evaluated to determine whether mapping images provided additional diagnostic information to PET alone (3-point scale). The overall quality of PET/CT or PET/MRI sets in diagnosis was also assessed (3-point scale). These PET/MRI-related scores were compared to PET/CT-related scores and the accuracy in characterizing PTs was compared.
Diffusion weighted MR imaging of pancreatic islet cell tumors
European Journal of Radiology, 2010
Purpose: The aim of our study is to demonstrate the feasibility of body diffusion weighted (DW) MR imaging in the evaluation of pancreatic islet cell tumors (ICTs) and to define apparent diffusion coefficient (ADC) values for these tumors. Materials and methods: 12 normal volunteers and 12 patients with histopathologically proven pancreatic ICT by surgery were included in the study. DW MR images were obtained by a body-phased array coil using a multisection single-shot echo planar sequence on the axial plane without breath holding. In addition, the routine abdominal imaging protocol for pancreas was applied in the patient group. We measured the ADC value within the normal pancreas in control group, pancreatic ICT, and surrounding pancreas parenchyma. Mann-Whitney U-test has been used to compare ADC values between tumoral tissues and normal pancreatic tissues of the volunteers. Wilcoxon Signed Ranks Test was preferred to compare ADC values between tumoral tissues and surrounding pancreatic parenchyma of the patients. Results: In 11 patients out of 12, conventional MR sequences were able to demonstrate ICTs succesfully. In 1 patient an indistinct suspicious lesion was noted at the pancreatic tail. DW sequence was able to demonstrate the lesions in all of the 12 patients. On the DW images, all ICTs demonstrated high signal intensity relative to the surrounding pancreatic parenchyma. The mean and standard deviations of the ADC values (×10 −3 mm 2 /s) were as follows: ICT (n = 12), 1.51 ± 0.35 (0.91-2.11), surrounding parenchyma (n = 11) 0.76 ± 0.15 (0.51-1.01) and normal pancreas in normal volunteers (n = 12), 0.80 ± 0.06 (0.72-0.90). ADC values of the ICT were significantly higher compared with those of surrounding parenchyma (p < 0.01) and normal pancreas (p < 0.001). Conclusion: DW MR imaging does not appear to provide significant contribution to routine MR imaging protocol in the evaluation of pancreatic islet cell tumors. But it can be added to MR imaging protocol to detect the lesion in a limited number of patients with clinical suspicion for pancreatic ICT with negative or suspicious imaging findings.
Incremental Value of 111-In Pentetreotide SPECT/CT Fusion Imaging of Neuroendocrine Tumors
Academic Radiology, 2010
Rationale and Objectives: Hybrid single photon-emission computed tomographic (SPECT) and computed tomographic (CT) imaging for the investigation of neuroendocrine tumors allows the fusion of functional and anatomic information in a rapid and efficient method. The aim of this study was to assess the incremental diagnostic value of 111 In pentetreotide SPECT/CT imaging compared with traditional planar and SPECT imaging with respect to lesion localization and characterization and reader confidence.
Physica Medica, 2020
To explore the variation of the discriminative power of CT radiomic features (RF) against image discretization/interpolation in characterizing pancreatic neuro-endocrine (PanNEN) neoplasms. Materials and methods: Thirty-nine PanNEN patients with pre-surgical high contrast CT available were considered. Image interpolation and discretization parameters were intentionally changed, including pixel size (0.73-2.19 mm 2), slice thickness (2-5 mm) and binning (32-128 grey levels) and their combination generated 27 parameter's set. The ability of 69 RF in discriminating post-surgically assessed tumor grade (> G1), positive nodes, metastases and vascular invasion was tested: AUC changes when changing the parameters were quantified for selected RF, significantly associated to each end-point. The analysis was repeated for the corresponding images with contrast medium and in a subgroup of 29/39 patients scanned on a single scanner. Results: The median tumor volume was 1.57 cm 3 (16%-84% percentiles: 0.62-34.58 cm 3). RF variability against discretization/interpolation parameters was large: only 21/69 RF showed %COV < 20%. Despite this variability, AUC changes were limited for all end-points: with typical AUC values around 0.75-0.85, AUC ranges for the 27 parameter's set were on average 0.062 (1SD:0.037) for all end-points with maximum %COV equal to 5.5% (mean:2.3%). Performances significantly improved when excluding the 5 mm thickness case and fixing the binning to 64 (mean AUC range: 0.036, 1SD:0.019). Using contrast images or limiting the population to singlescanner patients had limited impact on AUC variability. Conclusions: The discriminative power of CT RF for panNEN is relatively invariant against image interpolation/ discretization within a large range of voxel sizes and binning.
The Status of Neuroendocrine Tumor Imaging: From Darkness to Light?
Neuroendocrinology, 2014
Diagnostic imaging plays a pivotal role in diagnosis, staging, treatment selection and follow-up for neuroendocrine tumors (NETs). Diagnostic strategies that are available include morphologic imaging with CT, MRI, US techniques, and molecular imaging, with scintigraphy with 111 In-pentetreotide, PET with 68 Ga-DOTA-peptides, 18 F-DOPA and 11 C-5-HTP. A combination of anatomic and functional techniques is routinely performed to optimize sensitivity and specificity. The introduction of diffusion weighted imaging (DWI) MRI and dynamic contrast-enhanced (DCE) techniques represents promising advance in radiologic imaging whereas new receptor binding peptides, including somatostatin agonists and antagonists, represent the recent most favorable innovation in molecular imaging. Future development includes the short-term validation of these techniques but in extension also a more comprehensive multi-level integration of biologic information pertaining to a specific tumor and patient, possibly encompassing genomic considerations, currently evolving as a new entity denoted "precision medicine". The ideal is a diagnostic sequence that captures the global status of an individual's tumor and encompasses a multi-dimensional characterization of tumor location, metabolic performance and target identification. To date, advances in imagery have focused on increasing resolution, discrimination and functional characterization. In the future, the fusion of imagery with the parallel analysis of biological and genomic information has the potential to considerably amplify diagnosis.
2019
Purpose: To investigate the usefulness of contrastenhanced three-dimensional ultrasonography (CE 3D US) for differential diagnosis of solid pancreatic lesions. Methods: Eighty-five patients with solid pancreatic lesions who underwent CE 3D US were retrospectively analyzed. Sixty-four patients had pancreatic ductal adenocarcinoma (PDAC), 10 had mass-forming pancreatitis (MFP), and 11 had neuroendocrine tumor (NET). Two blinded readers evaluated the enhancement patterns using four features: vascularity in the arterial phase, vascularity in the venous phase, vessel location, and vessel form. Vascularity in both phases was classified as hypervascular, isovascular, or hypovascular. Vessel location was classified into peritumoral or intratumoral. Vessel form was classified into fine or irregular. Kappa values were used to assess inter-reader agreement. The institutional review board approved this study, and informed consent was obtained. Results: Kappa values of the four features were 0.75, 0.72, 0.85, and 0.65, which were graded as good or excellent. The most typical combined enhancement pattern in PDAC was hypovascularity in both phases with peritumoral and irregular vessels; MFP was isovascular in both phases with intratumoral and fine vessels; and NETs were hypervascular in both phases with intratumoral and irregular vessels. The sensitivity and positive predictive value of the three patterns were 93.8% and 96.7% for the PDAC pattern, 80.0% and 100% for the MFP pattern, and 81.8%, and 69.2% for the NET pattern, respectively. The accuracy of these diagnostic criteria was 90.5%. Conclusion: CE 3D US allows detailed visualization of the enhancement patterns of various pancreatic lesions and can be used for the differential diagnosis.
Physica Medica, 2019
The aim of this study was to quantify the impact of CT delineation uncertainty of pancreatic neuroendocrine neoplasms (panNEN) on Radiomic features (RF). Methods: Thirty-one previously operated patients were considered. Three expert radiologists contoured panNEN lesions on pre-surgical high-resolution contrast-enhanced CT images and contours were transferred onto precontrast CT. Volume agreement was quantified by the DICE index. After images resampling and re-binning, 69 RF were extracted and the impact of inter-observer variability was assessed by Intra-Class Correlation (ICC): ICC > 0.80 was considered as a threshold for "very high" inter-observer agreement. Results: The median volume was 1.3 cc (range: 0.2-110 cc); a satisfactory inter-observer volume agreement was found (mean DICE = 0.78). Only 4 RF showed ICC < 0.80 (0.48-0.73), including asphericity and three RFs (of five) of the neighborhood intensity difference matrix (NID). Conclusions: The impact of inter-observer variability in delineating panNEN on RF was minimum, with the exception of the NID family and asphericity, showing a moderate agreement. These results support the feasibility of studies aiming to assess CT radiomic biomarkers for panNEN.