Radiology of pancreatic adenocarcinoma: current status of imaging

Optimal conspicuity of pancreatic ductal adenocarcinoma in virtual monochromatic imaging reconstructions on a photon-counting detector CT: comparison to conventional MDCT

PURPOSE

To analyze the conspicuity of pancreatic ductal adenocarcinoma (PDAC) in virtual monoenergetic images (VMI) on a novel photon-counting detector CT (PCD-CT) in comparison to energy-integrating CT (EID-CT).

METHODS

Inclusion criteria comprised initial diagnosis of PDAC (reference standard: histopathological analysis) and standardized contrast-enhanced CT imaging either on an EID-CT or a PCD-CT. Patients were excluded due to different histopathological diagnosis or missing tumor delineation on CT. On the PCD-CT, 40-190 keV VMI reconstructions were generated. Image noise, tumor-to-pancreas ratio (TPR) and contrast-to-noise ratio (CNR) were analyzed by ROI-based measurements in arterial and portal venous contrast phase. Two board-certified radiologist evaluated image quality and tumor delineation at both, EID-CT and PCD-CT (40 and 70 keV).

RESULTS

Thirty-eight patients (mean age 70.4 years ± 10.3 [range 45-91], 27 males; PCD-CT: n=19, EID-CT: n=19) were retrospectively included. On the PCD-CT, tumor conspicuity (reflected by low TPR and high CNR) was significantly improved at low-energy VMI series (≤ 70 keV compared to > 70 keV), both in arterial and in portal venous contrast phase (P < 0.001), reaching the maximum at 40 keV. Comparison between PCD-CT and EID-CT showed significantly higher CNR on the PCD-CT in portal venous contrast phase at < 70 keV (P < 0.016). On the PCD-CT, tumor conspicuity was improved in portal venous contrast phase compared to arterial contrast phase especially at the lower end of the VMI spectrum (≤ 70 keV). Qualitative analysis revealed that tumor delineation is improved in 40 keV reconstructions compared to 70 keV reconstructions on a PCD-CT.

CONCLUSION

PCD-CT VMI reconstructions (≤ 70 keV) showed significantly improved conspicuity of PDAC in quantitative and qualitative analysis in both, arterial and portal venous contrast phase, compared to EID-CT, which may be important for early detection of tumor tissue in clinical routine. Tumor delineation was superior in portal venous contrast phase compared to arterial contrast phase.

Large Duct Pancreatic Ductal Adenocarcinoma: A Morphological Variant of Pancreatic Ductal Adenocarcinoma With Distinct CT and MRI Characteristics

OBJECTIVE

To investigate the imaging characteristics of large duct pancreatic ductal adenocarcinoma (LD-PDAC) on computed tomography (CT) and magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Thirty-five patients with LD-PDAC (63.2 ± 9.7 years) were retrospectively evaluated. Tumor morphology on CT and MRI (predominantly solid mass vs. solid mass with prominent cysts vs. predominantly cystic mass) was evaluated. Additionally, the visibility, quantity, shape (oval vs. branching vs. irregular), and MRI signal intensity of neoplastic cysts within the LD-PDAC were investigated. The radiological diagnoses rendered for LD-PDAC in radiology reports were reviewed.

RESULTS

LD-PDAC was more commonly observed as a solid mass with prominent cysts (45.7% [16/35] on CT and 37.1% [13/35] on MRI) or a predominantly cystic mass (20.0% [7/35] on CT and 40.0% [14/35] on MRI) and less commonly as a predominantly solid mass on CT (34.3% [12/35]) and MRI (22.9% [8/35]). The tumor morphology on imaging was significantly associated with the size of the cancer gland on histopathological examination (P = 0.020 [CT] and 0.013 [MRI]). Neoplastic cysts were visible in 88.6% (31/35) and 91.4% (32/35) of the LD-PDAC cases on CT and MRI, respectively. The cysts appeared as branching (51.6% [16/35] on CT and 59.4% [19/35] on MRI) or oval shapes (45.2% [14/35] on CT and 31.2% [10/35] on MRI) with fluid-like MRI signal intensity. In the radiology reports, 10 LD-PDAC cases (28.6%) were misinterpreted as diseases other than typical PDAC, particularly intraductal papillary mucinous neoplasms.

CONCLUSION

LD-PDAC frequently appears as a solid mass with prominent cysts or as a predominantly cystic mass on CT and MRI. Radiologists should be familiar with the imaging features of LD-PDAC to avoid misdiagnosis.

Use of individualized 3D-printed models of pancreatic cancer to improve surgeons' anatomic understanding and surgical planning

OBJECTIVES

Three-dimensional (3D) printing has been increasingly used to create accurate patient-specific 3D-printed models from medical imaging data. We aimed to evaluate the utility of 3D-printed models in the localization and understanding of pancreatic cancer for surgeons before pancreatic surgery.

METHODS

Between March and September 2021, we prospectively enrolled 10 patients with suspected pancreatic cancer who were scheduled for surgery. We created an individualized 3D-printed model from preoperative CT images. Six surgeons (three staff and three residents) evaluated the CT images before and after the presentation of the 3D-printed model using a 7-item questionnaire (understanding of anatomy and pancreatic cancer [Q1-4], preoperative planning [Q5], and education for trainees or patients [Q6-7]) on a 5-point scale. Survey scores on Q1-5 before and after the presentation of the 3D-printed model were compared. Q6-7 assessed the 3D-printed model's effects on education compared to CT. Subgroup analysis was performed between staff and residents.

RESULTS

After the 3D-printed model presentation, survey scores improved in all five questions (before 3.90 vs. after 4.56, p < 0.001), with a mean improvement of 0.57‒0.93. Staff and resident scores improved after a 3D-printed model presentation (p < 0.05), except for Q4 in the resident group. The mean difference was higher among the staff than among the residents (staff: 0.50‒0.97 vs. residents: 0.27‒0.90). The scores of the 3D-printed model for education were high (trainees: 4.47 vs. patients: 4.60) compared to CT.

CONCLUSION

The 3D-printed model of pancreatic cancer improved surgeons' understanding of individual patients' pancreatic cancer and surgical planning.

CLINICAL RELEVANCE STATEMENT

The 3D-printed model of pancreatic cancer can be created using a preoperative CT image, which not only assists surgeons in surgical planning but also serves as a valuable educational resource for patients and students.

KEY POINTS

• A personalized 3D-printed pancreatic cancer model provides more intuitive information than CT, allowing surgeons to better visualize the tumor's location and relationship to neighboring organs. • In particular, the survey score was higher among staff who performed the surgery than among residents. • Individual patient pancreatic cancer models have the potential to be used for personalized patient education as well as resident education.

An Automated Prognostic Model for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) constitutes a leading cause of cancer-related mortality despite advances in detection and treatment methods. While computed tomography (CT) serves as the current gold standard for initial evaluation of PDAC, its prognostic value remains limited, as it relies on diagnostic stage parameters encompassing tumor size, lymph node involvement, and metastasis. Radiomics have recently shown promise in predicting postoperative survival of PDAC patients; however, they rely on manual pancreas and tumor delineation by clinicians. In this study, we collected a dataset of pre-operative CT scans from a cohort of 40 PDAC patients to evaluate a fully automated pipeline for survival prediction. Employing nnU-Net trained on an external dataset, we generated automated pancreas and tumor segmentations. Subsequently, we extracted 854 radiomic features from each segmentation, which we narrowed down to 29 via feature selection. We then combined these features with the Tumor, Node, Metastasis (TNM) system staging parameters, as well as the patient's age. We trained a random survival forest model to perform an overall survival prediction over time, as well as a random forest classifier for the binary classification of two-year survival, using repeated cross-validation for evaluation. Our results exhibited promise, with a mean C-index of 0.731 for survival modeling and a mean accuracy of 0.76 in two-year survival prediction, providing evidence of the feasibility and potential efficacy of a fully automated pipeline for PDAC prognostication. By eliminating the labor-intensive manual segmentation process, our streamlined pipeline demonstrates an efficient and accurate prognostication process, laying the foundation for future research endeavors.

Accelerated Pancreatobiliary MRI for Pancreatic Cancer Surveillance in Patients With Pancreatic Cystic Neoplasms

BACKGROUND

Pancreatobiliary MRI is often recommended for patients at risk of developing pancreas cancer. But the surveillance MRI protocol has not yet been widely accepted.

PURPOSE

To establish an accelerated MRI protocol targeting the table time of 15 minutes for pancreatic cancer surveillance and test its performance in lesion characterization.

STUDY TYPE

Prospective.

POPULATION

A total of 30 participants were enrolled, who were undergoing follow-up care for intraductal papillary mucinous neoplasms or newly diagnosed pancreatic cysts (≥10 mm) and were scheduled for or had recently undergone contrast-enhanced CT (CECT).

FIELD STRENGTH/SEQUENCE

A 3 T; heavily T2WI, 3D MRCP, DWI, dynamic T1WI, two-point Dixon.

ASSESSMENT

In-room time and table time were measured. Seven radiologists independently reviewed image quality of MRI and then the presence of high-risk stigmata and worrisome features in addition to diagnostic confidence for accelerated MRI, CECT, and the noncontrast part of accelerated MRI (NC-MRI).

STATISTICAL ANALYSIS

Fisher's exact test was used for categorical variables and either the Student's t-test or Mann-Whitney test was performed for continuous variables. The generalized estimated equation was used to compare the diagnostic performance of examinations on a per-patient basis. Interobserver agreement was evaluated via Fleiss kappa. A P value of <0.05 was considered to be statistically significant.

RESULTS

The in-room time was 18.5 ± 2.6 minutes (range: 13.7-24.9) and the table time was 13.9 ± 1.9 minutes (range: 10.7-17.5). There was no significant difference between the diagnostic performances of the three examinations (pooled sensitivity: 75% for accelerated MRI and CECT, 68% for NC-MRI, P = 0.95), with the highest significant diagnostic confidence for accelerated MRI (4.2 ± 0.1). With accelerated MRI, the interobserver agreement was fair to excellent for high-risk stigmata (κ = 0.34-0.98).

DATA CONCLUSION

Accelerated MRI protocol affords a table time of 15 minutes, making it potentially suitable for cancer surveillance in patients at risk of developing pancreatic cancer.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY STAGE: 2.

Systematic review and meta-analysis of diagnostic performance of CT imaging for assessing resectability of pancreatic ductal adenocarcinoma after neoadjuvant therapy: importance of CT criteria

PURPOSE

To assess the CT diagnostic performance for evaluating resectability of pancreatic ductal adenocarcinoma (PDAC) after neoadjuvant therapy and identify the factor(s) that affect(s) diagnostic performance.

METHODS

Databases were searched to identify studies published from January 1, 2000, to November 5, 2019 that evaluated the CT diagnostic performance for assessing resectability of post-neoadjuvant PDAC. Two reviewers independently extracted data and assessed the study quality. A meta-analysis was performed to obtain summary sensitivity and specificity values using a bivariate random-effects model, and heterogeneity across studies was assessed. Univariable meta-regression analysis was performed with eight variables, including the different CT criteria for resectability, conventional National Comprehensive Cancer Network (NCCN) criteria for upfront surgery, and modified criteria for post-neoadjuvant surgery.

RESULTS

Ten studies were included and analyzed. The summary sensitivity and specificity for resectability were 78% (95% CI 68-86%) and 60% (95% CI 44-74%), respectively. No significant heterogeneity was identified (bivariate correlation coefficient ρ = - 1, p-value for hierarchical summary receiver operating characteristics model β = 0.667). The two different CT criteria showed different diagnostic performance (p < 0.01), with higher sensitivity (81% [95% CI 73-90%] vs. 28% [95% CI 15-42%], p < 0.01) and lower specificity (57% [95% CI 41-73%] vs. 90% [95% CI 80-100%], p < 0.01) for the modified criteria. No other variables affected the diagnostic performance.

CONCLUSION

CT criteria were the factors that affected the diagnostic performance. Modification of the conventional criteria improved sensitivity but lowered specificity. Further modifications are required to improve specificity and uniformity.

Identification of intratumoral fluid-containing area by magnetic resonance imaging to predict prognosis in patients with pancreatic ductal adenocarcinoma after curative resection

OBJECTIVES

To compare the prognosis of pancreatic ductal adenocarcinoma (PDAC) after curative resection according to the type of intratumoral fluid-containing area identified on MRI.

METHODS

This retrospective study included 112 consecutive patients who underwent upfront surgery with margin-negative resection between 2012 and 2019. All patients underwent MRI within 1 month before surgery. Three radiologists independently assessed the MRI findings, determined whether intratumoral fluid-containing areas were present, and classified all intratumoral fluid-containing areas by type (i.e., imaging necrosis or neoplastic mucin cysts). Recurrence-free survival (RFS) and overall survival (OS) were evaluated by the Kaplan-Meier method and the Cox proportional hazards model. Histopathological differences according to the type of intratumoral fluid-containing area were assessed.

RESULTS

Of the 112 PDAC patients, intratumoral fluid-containing areas were identified on MRI in 33 (29.5%), among which 18 were classified as imaging necrosis and 15 as neoplastic mucin cysts. PDAC patients with imaging necrosis demonstrated significantly shorter RFS (mean 6.1 months versus 47.3 months; p < .001) and OS (18.4 months versus 55.0 months, p = .001) than those with neoplastic mucin cysts. Multivariable analysis showed that only the type of intratumoral fluid-containing area was significantly associated with RFS (hazard ratio, 2.25 and 0.38; p = .009 and p = .046 for imaging necrosis and neoplastic mucin cysts, respectively). PDAC with imaging necrosis had more frequent histological necrosis, more aggressive tumor differentiation, and higher tumor cellularity than PDAC with neoplastic mucin cysts (p ≤ .02).

CONCLUSION

The detection and discrimination of intratumoral fluid-containing areas on preoperative MRI may be useful in predicting the prognosis of PDAC patients after curative resection.

KEY POINTS

• Pancreatic ductal adenocarcinoma (PDAC) patients with imaging necrosis demonstrated significantly shorter survival than those with neoplastic mucin cysts after curative resection. • Multivariable analysis showed that only the type of intratumoral fluid-containing area identified on MRI was significantly associated with recurrence-free survival. • PDAC with imaging necrosis had more frequent histological necrosis, more aggressive tumor differentiation, and higher tumor cellularity than PDAC with neoplastic mucin cysts.

Diagnostic Performance of EUS-Guided Sampling in Indeterminate Radiological Diagnosis of Pancreatic Disease and Intra-Abdominal Lymphadenopathy

BACKGROUND

Endoscopic ultrasound (EUS)-guided sampling has been widely used for pathologic diagnosis of pancreatic lesions and intra-abdominal lymphadenopathy. However, its effectiveness for diagnostic decision making in indeterminate radiological diagnosis has not been well determined.

MATERIALS AND METHODS

From March 2012 to October 2015, 98 consecutive patients who underwent EUS-guided FNA for solid intra-abdominal lesions were retrospectively analyzed (100 procedures). The purpose of EUS-guided sampling was classified as (1) confirmation of a high-confidence radiological diagnosis (High-confidence group) or (2) decision making in the differential diagnostic dilemma for indeterminate radiological diagnosis (Indeterminate group). The accuracies of EUS-guided sampling according to the purpose were analyzed and then compared.

RESULTS

Of the 100 procedures, 22 procedures (22%) came under the Indeterminate group, whereas 78 came under the High-confidence group. The accuracies did not differ between the Indeterminate and the High-confidence groups (86.4% vs. 88.5%, p = 1.000). Clinical conditions that required EUS-guided sampling for indeterminate radiological diagnosis were (1) pancreatic cancer vs. benign disease (n = 8; e.g., pancreatic cancer vs. mass-forming pancreatitis), (2) recurrence of previous/pre-existing cancer vs. benign disease (n = 5; e.g., recurrent gastric cancer vs. reactive lymph node), (3) pathologic differentiation of presumed malignancy (n = 6; e.g., lymphadenopathies in the previous history of esophageal cancer and colon cancer), or (4) miscellaneous (n = 3; e.g., tuberculous lymphadenopathy vs. other condition).

CONCLUSIONS

EUS-guided sampling demonstrated an accuracy of 86.4% in the clinical setting of indeterminate radiological diagnosis, which was not different from that of the confirmation of high-confidence diagnosis.

Minimally invasive image-guided therapy of primary and metastatic pancreatic cancer

Pancreatic cancer is a challenging malignancy with limited treatment options and poor life expectancy. The only curative option is surgical resection, but only 15%-20% of patients are resectable at presentation because more than 50% of patients has distant metastasis at diagnosis and the rest of them has locally advanced pancreatic cancer (LAPC). The standard of care first line treatment for LAPC patients is chemotherapy with or without radiation therapy. Recent developments in minimally invasive ablative techniques may add to the treatment armamentarium of LAPC. There are increasing number of studies evaluating these novel ablative techniques, including radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation. Most studies which included pancreatic tumor ablation, demonstrated improved overall survival in LAPC patients. However, the exact protocols are yet to set up to which stage of the treatment algorithm ablative techniques can be added and in what kind of treatment combinations. Patients with metastatic pancreatic cancer has dismal prognosis with 5-year survival is only 3%. The most common metastatic site is the liver as 90% of pancreatic cancer patients develop liver metastasis. Chemotherapy is the primary treatment option for patients with metastatic pancreatic cancer. However, when the tumor is not responding to chemotherapy or severe drug toxicity develops, locoregional liver-directed therapies can provide an opportunity to control intrahepatic disease progression and improve survival in selected patients. During the last decade new therapeutic options arose with the advancement of minimally invasive technologies to treat pancreatic cancer patients. These new therapies have been a topic of increasing interest due to the severe prognostic implications of locally advanced and metastatic pancreatic cancer and the low comorbid risk of these procedures. This review summarizes new ablative options for patients with LAPC and percutaneous liver-directed therapies for patients with liver-dominant metastatic disease.

Retrospective evaluation of venous phase contrast-enhanced computed tomography images in patients who developed pancreatic adenocarcinomas after treatment for nonpancreatic primary cancer

Objectives:

To clarify venous phase contrast-enhanced CT findings in early pancreatic adenocarcinomas by retrospectively evaluating CT images of pancreatic adenocarcinomas that developed during follow-up after treatment for non-pancreatic cancers.

Methods:

The study cohort comprised six patients who developed pancreatic adenocarcinomas between April 2005 and April 2020 during follow-up after treatment for non-pancreatic primary cancers. Two radiologists retrospectively evaluated CT images and reached consensus on previously reported CT findings that were suggestive of small pancreatic adenocarcinomas; namely pancreatic duct interruption and dilatation, pancreatic parenchymal atrophy, focal hypoattenuated areas, and appearance of cystic lesions. Time intervals between the first CT with these suggestive findings and the latest pre-operative CT were recorded. Doubling times were calculated in patients with hypoattenuated areas on initial CT scans.

Results:

Small (<10 mm) focal hypoattenuated areas with (n = 2) or without rim enhancement (n = 1) were identified on initial CT images of three patients. Pancreatic duct interruption and dilatation, pancreatic parenchymal atrophy, and cystic lesion were identified in two, one and one patient, respectively. Time intervals between initial and latest preoperative CT examination were 6–19 months (median, 14.5 months). Tumor doubling time according to CT findings was calculated as 46–407 days (median 106 days).

Conclusion:

Venous phase contrast-enhanced CT can provide findings that are suggestive of early pancreatic adenocarcinoma. Pancreatic phase contrast-enhanced CT should therefore be performed in patients with such findings with the aim of early detection of pancreatic adenocarcinoma.

Advances in knowledge:

Pancreatic adenocarcinoma can develop subsequently in patients with non-pancreatic malignancies. Patients with non-pancreatic cancers are often followed up with monophasic contrast-enhanced CT in venous phase timing. Venous phase contrast-enhanced CT can provide some findings suggestive of early pancreatic adenocarcinoma. Knowledge of these findings is important for early detection of pancreatic adenocarcinoma.

Curing pancreatic cancer

The distinct biology of pancreatic cancer with aggressive and early invasive tumor cells, a tumor promoting microenvironment, late diagnosis, and high therapy resistance poses major challenges on clinicians, researchers, and patients. In current clinical practice, a curative approach for pancreatic cancer can only be offered to a minority of patients and even for those patients, the long-term outcome is grim. This bitter combination will eventually let pancreatic cancer rise to the second leading cause of cancer-related mortalities. With surgery being the only curative option, complete tumor resection still remains the center of pancreatic cancer treatment. In recent years, new developments in neoadjuvant and adjuvant treatment have emerged. Together with improved perioperative care including complication management, an increasing number of patients have become eligible for tumor resection. Basic research aims to further increase these numbers by new methods of early detection, better tumor modelling and personalized treatment options. This review aims to summarize the current knowledge on clinical and biologic features, surgical and non-surgical treatment options, and the improved collaboration of clinicians and basic researchers in pancreatic cancer that will hopefully result in more successful ways of curing pancreatic cancer.

Improved detectability of hypoattenuating focal pancreatic lesions by dual-layer computed tomography using virtual monoenergetic images

Background

Multidetector CT is the mainstay for radiologic evaluation of pancreatic pathology. Still, imaging of focal pancreatic lesions using MDCT is faced by a number of challenges that are related to the limited contrast between the lesion and surrounding parenchyma, such as detecting early-stage pancreatic cancer and subtle features of cystic lesions that point to malignancy. Dual-layer CT is the first dual-energy CT machine based on separation of high- and low-energy photons at the detector level. If improved contrast between the lesions and normal pancreatic parenchyma could be achieved on CT images, we may expect enhanced CT detection of pancreatic lesions. The purpose of this study was to evaluate whether virtual monoenergetic reconstructions generated using contrast-enhanced dual-layer CT could improve detectability of hypoattenuating focal pancreatic lesions compared to conventional polyenergetic reconstructions.

Results

Fifty-four lesions were identified and verified by histopathology or follow-up CT, MRCP, and/or EUS along with clinical data. Across the virtual monoenergetic spectrum, 40 KeV images had the highest contrast-to-noise and signal-to-noise ratios (p < 0.001, p < 0.001) and were significantly higher than conventional images (p < 0.001). Subjective scores for lesion visibility at low kiloelectron volt monoenergetic (40 and 50 KeV) images greatly exceeded conventional images (p < 0.001).

Conclusion

Low kiloelectron volt monoenergetic reconstructions of contrast-enhanced dual-layer CT significantly improve detectability of hypoattenuating focal pancreatic lesions compared to conventional polyenergetic reconstructions.

Perioperative CT angiography assessment of locally advanced distal pancreatic carcinoma to evaluate feasibility of the modified Appleby procedure

PURPOSE

To study the perioperative CT angiography (CTA) findings of modified Appleby procedure candidates for the surgical feasibility in patients with locally advanced distal pancreatic cancer (LAPC) and to assess CTA performance.

MATERIALS AND METHODS

This retrospective study evaluated CTA of patients with distal LAPC who underwent modified Appleby procedure between March 2004 and October 2017. Preoperative CT scans performed within up to three months prior to the surgery and postoperative scans, at least one of which was within one month of surgery, were reviewed. Data was collected reporting tumor size, relation to vessels, changes from neoadjuvant chemoradiation, modifications to the surgery and complications. The CTA findings were correlated with operative notes and surgical pathology. Statistical analysis was performed using binary classification method to evaluate CTA performance.

RESULTS

Consecutive 20 patients underwent modified Appleby procedure in the study period. In 18/20 patients who received neoadjuvant chemoradiation, mean pancreatic mass size significantly reduced from 4.58 + 1.17 cm to 3.55 + 0.84 cm (p = 0.002). The celiac axis (CA) was encased in all, whereas none of the patients had encasement of the superior mesenteric artery (SMA) or involvement of gastroduodenal artery (GDA). The CTA had 88.89% sensitivity, 100% specificity, and 90% accuracy for evaluating the arterial involvement.

CONCLUSION

Distal LAPC patients, in particular those who have significant size reduction after neoadjuvant chemoradiation, with encasement of CA and without encasement of SMA and GDA can undergo a technically successful modified Appleby procedure. CTA offers accurate and valuable perioperative assessment of the surgical candidates.

Preoperative imaging characteristics predict poor survival and inadequate resection for left-sided pancreatic adenocarcinoma: a multi-institutional analysis

BACKGROUND

Optimal treatment of pancreatic ductal adenocarcinoma of the neck, body and tail (PDAC-NBT) necessitates R0 surgical resection. Preoperative radiographic identification of patients likely to achieve successful oncologic resection remains difficult. This study seeks to identify preoperative imaging characteristics predictive of non-R0 resections or impaired survival for PDAC-NBT.

METHODS

Patients at five high-volume centers who underwent resection for PDAC-NBT were retrospectively analyzed. The most immediate preoperative cross-sectional scan was assessed along with outcome measures of overall survival and margin status.

RESULTS

330 patients were treated between 2001 and 2016. Margin status included 247 R0 (78.2%), 67 R1 (21.2%), and 2 R2 (0.6%). A non-R0 resection predicted worse survival (p = 0.0002). On preoperative imaging, patients with tumors greater than 20 mm, tumor attenuation greater than 70 Hounsfield units, or who demonstrated pancreatic atrophy and/or calcifications also had worse survival (p = 0.010, p = 0.036, p = 0.025 respectively). Patients with tumors interfacing with the splenic artery or vein or extending posteriorly achieved fewer R0 resections (p = 0.0006, p = 0.0004, p = 0.001, respectively).

CONCLUSION

Preoperative cross-sectional imaging can identify tumor characteristics associated with poor survival and non-R0 resection. Further investigation is needed to identify the appropriate surgical and treatment modifications necessary to clinically benefit this subset of patients.

Tumor conspicuity significantly correlates with postoperative recurrence in patients with pancreatic cancer: a retrospective observational study

BACKGROUND

There has been scanty data regarding the clinical significance of tumor conspicuity in pancreatic cancer. In this study, we attempted to investigate the prognostic significance of pancreatic tumor conspicuity and determine prognostic factors for postoperative recurrence in patients with surgically resected pancreatic cancer.

METHODS

Between January 2011 and September 2019, 62 patients who underwent preoperative computed tomography (CT) for pancreatic cancer were retrospectively included. Two reviewers evaluated various clinical, imaging, and pathologic variables and reviewed all available medical records to determine patient outcomes after surgery. Tumor conspicuity was defined as the attenuation ratio between normal parenchyma and tumor lesions on dynamic-enhanced CT images and represented the conspicuity score. Recurrence-free survival and overall survival were investigated using Cox regression analysis.

RESULTS

Patient mean age was 65.9 (±11.6) years, and 56.5% were male. The median follow-up period was 11 months (range 2-138). Forty patients (64.5%) experienced postoperative recurrence, and the median time to recurrence was 6 months (range 1-101). Tumor conspicuity scores were positively correlated with both radiologic and pathologic tumor sizes (r = 0.252, 0.321, p < 0.01). Conspicuity score ≥ 2 (HR 3.8, 95% CI 1.73-8.47), elevated preoperative (HR 1.15, 95% CI; 1.02-1.28) and postoperative CA19-9 (HR 1.11, 95% CI 1.01-1.23), pathologic tumor size (HR 1.61, 95% CI 1.06-2.45), and lymphatic invasion (HR 2.76, 95% CI 1.22-6.21) were significant factors for recurrence-free survival in the multivariate analysis.

CONCLUSIONS

Over half of the patients with pancreatic cancer experienced postoperative recurrence (64.5%). Increased tumor conspicuity correlated with larger tumor size and postoperative recurrence.

Diffusion Kurtosis Imaging-A Superior Approach to Assess Tumor-Stroma Ratio in Pancreatic Ductal Adenocarcinoma

Extensive desmoplastic stroma is a hallmark of pancreatic ductal adenocarcinoma (PDAC) and contributes to tumor progression and to the relative resistance of tumor cells towards (radio) chemotherapy. Thus, therapies that target the stroma are under intense investigation. To allow the stratification of patients who would profit from such therapies, non-invasive methods assessing the stroma content in relation to tumor mass are required. In the current prospective study, we investigated the usefulness of diffusion-weighted magnetic resonance imaging (DW-MRI), a radiologic method that measures the random motion of water molecules in tissue, in the assessment of PDAC lesions, and more specifically in the desmoplastic tumor stroma. We made use of a sophisticated DW-MRI approach, the so-called diffusion kurtosis imaging (DKI), which possesses potential advantages over conventional and widely used monoexponential diffusion-weighted imaging analysis (cDWI). We found that the diffusion constant D from DKI is highly negatively correlated with the percentage of tumor stroma, the latter determined by histology. D performed significantly better than the widely used apparent diffusion coefficient (ADC) from cDWI in distinguishing stroma-rich (>50% stroma percentage) from stroma-poor tumors (≤50% stroma percentage). Moreover, we could prove the potential of the diffusion constant D as a clinically useful imaging parameter for the differentiation of PDAC-lesions from non-neoplastic pancreatic parenchyma. Therefore, the diffusion constant D from DKI could represent a valuable non-invasive imaging biomarker for assessment of stroma content in PDAC, which is applicable for the clinical diagnostic of PDAC.

Imaging diagnosis and staging of pancreatic ductal adenocarcinoma: a comprehensive review

Pancreatic ductal adenocarcinoma (PDAC) has continued to have a poor prognosis for the last few decades in spite of recent advances in different imaging modalities mainly due to difficulty in early diagnosis and aggressive biological behavior. Early PDAC can be missed on CT due to similar attenuation relative to the normal pancreas, small size, or hidden location in the uncinate process. Tumor resectability and its contingency on the vascular invasion most commonly assessed with multi-phasic thin-slice CT is a continuously changing concept, particularly in the era of frequent neoadjuvant therapy. Coexistent celiac artery stenosis may affect the surgical plan in patients undergoing pancreaticoduodenectomy. In this review, we discuss the challenges related to the imaging of PDAC. These include radiological and clinical subtleties of the tumor, evolving imaging criteria for tumor resectability, preoperative diagnosis of accompanying celiac artery stenosis, and post-neoadjuvant therapy imaging. For each category, the key imaging features and potential pitfalls on cross-sectional imaging will be discussed. Also, we will describe the imaging discriminators of potential mimickers of PDAC.

Dual-Energy CT of the Pancreas

This article explores the technical background of dual-energy CT (DECT) imaging along with its basic principles, before turning to a review of the various DECT applications specific to pancreatic imaging. In light of the most recent literature, we will review the constellation of DECT applications available for pancreatic imaging in both oncologic and non-oncologic applications. We emphasize the increased lesion conspicuity and the improved tissue characterization available with DECT post-processing tools. Finally, future clinical applications and opportunities for research will be overviewed.

Double contrast-enhanced ultrasound improves the detection and localization of occult lesions in the pancreatic tail: a initial experience report

PURPOSE

The aim of this study is to review our initial experience of Double contrast-enhanced ultrasonography (DCEUS) in the preoperative detection of pancreatic tail occult tumors.

METHODS

Thirty-five patients were recruited to undergo DCEUS of the pancreas suspected by occult lesions of pancreatic with MRI or clinical evidence. The radiologists assessed the images (conventional US, DCEUS, and MRI) for enhancement phases, tumor presence, location, enhancement characteristics, and tumor conspicuity. The differences in the onset times of the phases between DCEUS and MRI were noted. Tumor conspicuity was graded on a four-point scale for conspicuity comparison among three imaging modalities.

RESULTS

Pancreatic tail tumors were missed on conventional transabdominal US in 11 of 35 patients. DCEUS revealed 12 lesions of 35 patients. Pancreatic tail tumors were identified on MRI in 10 of 35 patients. The sensitivity and specificity of DCEUS for depicting occult lesions of ≤ 2.2 cm were 92% and 95%, respectively. In contrast, the sensitivity and specificity of conventional US were 67% and 66%, respectively. The sensitivity and specificity of MRI were 91% and 88%, respectively. The conspicuity ratings of the three phases did not significantly differ between the DCEUS and MRI groups (P > 0.05). The DCEUS phases started much earlier than the corresponding MRI phases.

CONCLUSION

DCEUS is a promising technique in the detection of occult pancreatic tail tumors and is possibly superior to dynamic enhanced MRI in the case of some peripheral lesions.

Lower energy levels and iodine-based material decomposition images increase pancreatic ductal adenocarcinoma conspicuity on rapid kV-switching dual-energy CT

PURPOSE

Multidetector computed tomography (MDCT) is used in the diagnosis of pancreatic ductal adenocarcinoma (PDAC), but it may be inadequate in some cases. Tumor detection can be improved using rapid kV-switching dual-energy CT (rsDECT) and iodine maps. Our aim this study is to evaluate tumor conspicuity in PDAC cases using rsDECT and iodine maps.

METHODS

Ninety cases with PDAC were evaluated rsDECT. Tumor contrast (HU) differences, tumor size, CNR (contrast-noise ratio), and noise were measured at 70 keV, individual CNR-energy level, and 45 keV, respectively. Quantitative differences in contrast gain ∆70-CNR and ∆CNR-45 were compared. On iodine maps, the iodine concentration measured in the tumor and parenchyma was normalized to the aorta as normalized iodine concentration (NIC) and compared.

RESULTS

The median optimized viewing energy level was 51 keV. The mean ± SD tumor contrast values were 62 ± 20, 115 ± 48, and 152 ± 48 HU (p < 0.001); the largest axial diameters were 36.6 ± 5.1, 37.9 ± 4.2, and 38.3 ± 3.7 mm (p = 0.015); the CNRs were 1.83 ± 0.72, 3.37 ± 0.93, and 2.36 ± 0.56; and the image noise levels were 23.7 ± 6.8, 39.3 ± 11.6, and 59.5 ± 17.2 (p < 0.001) (p < 0.001) for 70 keV, optimized energy level, and 45 keV, respectively. The mean ± SD contrast gain ∆70-CNR was 63 ± 12; and ∆CNR-45 was 31 ± 26 HU (p < 0.001). NIC_tumor and NIC_parenchyma values were 0.62 ± 0.03 and 1.36 ± 0.05 mg/mL, respectively (p = 0.004).

CONCLUSION

The use of low energy levels on rsDECT and iodine maps improves tumor conspicuity. This situation may be help better detection of pancreatic tumors.

Stromal Content Is Correlated With Tissue Site, Contrast Retention, and Survival in Pancreatic Adenocarcinoma

PURPOSE

Desmoplastic stroma is a cardinal feature of primary pancreatic ductal adenocarcinoma (PDAC), but its effects on the biology, prognosis and therapeutic outcomes are not known. We developed an automated method to assess tumor stroma density (TSD) and investigated computed tomography (CT)-correlates of stroma in PDAC.

PATIENTS AND METHODS

We collected PDAC samples from rapid autopsy and resection series and digitally annotated samples to quantify TSD. A series of resected patients also underwent preoperative multiphasic CT.

RESULTS

Automated and manual assessments of TSD were highly correlated (ρ= 0.65, P < 0.001). Solid organ metastases had a lower median TSD than primary tumors (P < 0.001). Patients with high TSD enjoyed prolonged recurrence free survival (RFS) (P = 0.003; HR = 0.51) and overall survival (P = 0.008, HR = 0.57). In another independent dataset, patients with high TSD had decreased risk for recurrence (P = 0.003, HR = 0.03) and death (P = 0.003, HR = 0.03) at time of resection, however the protective effect diminished over time. Patients with normalized portovenous phase CT tumor enhancement ratio ≥0.40 had a longer RFS following resection (P = 0.020). Normalized portovenous phase CT tumor enhancement ratio was significantly correlated with TSD (P = 0.003).

CONCLUSIONS

Objective quantitative assessment of stroma in PDAC revealed several clinically relevant observations. Firstly, stroma was less abundant in metastatic PDAC, the cause of most PDAC mortality. Secondly, high stromal content correlates with favorable outcome in resected cases, implying a protective effect of stroma and suggesting careful consideration of active stromal depletion therapies. Finally, standard multiphase CT imaging correlates with stroma content as well as clinical outcome, indicating that non-invasive assessment of stroma is a feasible sensitivity enrichment approach in PDAC.

Pancreatic Cancer Diagnosis and Management: Has the Time Come to Prick the Bubble?

Pancreatic cancer (PC) is associated with poor prognosis and very dismal survival rates. The most effective possibility of cure is tumor resection, which is only possible in about 15% of patients diagnosed at early stages of disease progression. Recent whole-genome sequencing studies pointed genetic alterations in 12 core signaling pathways in PC. These observations hint at the possibility that the initial mutation in PC might appear nearly 20 years before any symptoms occur, suggesting that a large window of opportunity may exist for early detection. Biomarkers with the potential to identify pre-neoplastic disease or very early stages of cancer are of great promise to improve patient survival. The concept of liquid biopsy refers to a minimally invasive sampling and analysis of liquid biomarkers that can be isolated from body fluids, primarily blood, urine and saliva. A myriad of circulating molecules may be useful as tumor markers, including cell-free DNA (cfDNA), cell-free RNA (cfRNA), circulating tumor cells (CTC), circulating tumor proteins, and extracellular vesicles, more specifically exosomes. In this review, we discuss with more detail the potential role of exosomes in several aspects related to PC, from initiation to tumor progression and its applicability in early detection and treatment. Exosomes are small circulating extracellular vesicles of 50-150 nm in diameter released from the plasma membrane by almost all cells and exhibit some advantages over other biomarkers. Exosomes are central players of intercellular communication and they have been implicated in a series of biological process, including tumorigenesis, migration and metastasis. Several exosomal microRNAs and proteins have been observed to distinguish PC from benign pancreatic diseases and healthy controls. Besides their possible role in diagnosis, understanding exosomes functions in cancer has clarified the importance of microenvironment in PC progression as well as its influence in proliferation, metastasis and resistance to chemotherapy. Increasing knowledge on cancer exosomes provides valuable insights on new therapeutic targets and can potentially open new strategies to treat this disease. Continuous research is needed to ascertain the reliability of using exosomes and their content as potential biomarkers, so that, hopefully, in the near future, they will provide the opportunity for early diagnosis, treatment intervention and increase survival of PC patients.

Staging pancreatic carcinoma by computed tomography

Pancreatic carcinoma is becoming more common in our environment; the mortality rate for this tumor has barely changed over the last 20 years. Early diagnosis and accurate staging are crucial to ensure an appropriate therapeutic approach, which should aim to improve survival in patients in whom complete resection is possible and to minimize surgical morbidity and mortality in those with a high risk of residual disease after the intervention. Various imaging techniques are used for tumor staging: multidetector computed tomography (CT), magnetic resonance imaging, positron emission tomography (PET)-CT, endoscopic ultrasound, and diagnostic laparoscopy. Currently, multidetector CT is the technique of choice for the study of pancreatic tumors; thus, this article aims to review the state of the art in staging adenocarcinoma of the pancreas, focusing mainly on the applications and limitations of this technique.

The Etiologic Evaluation of Acute Pancreatitis in a General Hospital of Seoul-Gyeonggi Province in Korea

Background/Aims

In recent years, the incidence of acute pancreatitis (AP) has been increasing. A better understanding of the etiology is directly linked to more favorable outcomes. Unfortunately, there have been reports suggesting the variation of etiologies of AP across countries. The objective of this study was to determine the etiology of AP in a general hospital of Seoul-Gyeonggi province in Korea during the past decade.

Methods

We retrospectively reviewed the medical records of consecutive patients with AP who were admitted to St. Paul's Hospital (Seoul, Korea) with an affiliation to the Catholic University of Korea between January 2003 and January 2013.

Results

A total of 1,110 patients were enrolled, totaling 1,833 attacks, and the most frequent cause of AP was alcohol consumption. The recurrence rate of AP was 24.5% (272/1,110), and habitual recurrence rate (more than three times) was 12.6% (140/1,110). The rate of severe AP was 4.9% (90/1,833 attacks). The mortality rate of AP was 2.6% (29/1,110 patients). The frequency of an idiopathic cause of AP was 13.3%. The recurrence rate and mortality rate of idiopathic AP were 16.2% and 5.4%, respectively. In 41.7% (10/24) of cases of idiopathic AP, microlithiasis was suspected.

Conclusions

Between 2003 and 2013 in Korea, alcohol was the most frequent cause of AP in the general hospital of Seoul-Gyeonggi province of Korea. It appears that alcohol abstinence program may be necessary. Further nationwide studies would be needed to evaluate the etiologies of AP.

Percutaneous Radiofrequency Ablation of Unresectable Locally Advanced Pancreatic Cancer: Preliminary Results

AIM

The objective of this study was to evaluate the efficacy of percutaneous radiofrequency ablation of locally advanced pancreatic cancer located in the pancreatic body.

MATERIALS AND METHODS

Patients with biopsy-proven locally advanced pancreatic adenocarcinoma were considered for percutaneous radiofrequency ablation. Postprocedural computed tomography studies and Ca19.9 tumor marker evaluation were performed at 24 hours and 1 month. At computed tomography, treatment effect was evaluated by excluding the presence of complications. The technical success of the procedure is defined at computed tomography as the achievement of tumoral ablated area.

RESULTS

Twenty-three patients have been included in the study. Five of the 23 patients were excluded. At computed tomography, the mean size of the intralesional postablation necrotic area was 32 mm (range: 15-65 mm). Technical success of the procedure has been obtained in 16 (93%) of the 18 cases. None of the patients developed postprocedural complications. Mean Ca19.9 serum levels 1 day before, 1 day after, and 1 month after the procedure were 285.8 U/mL (range: 16.6-942.0 U/mL), 635.2 U/mL (range: 17.9-3368.0 U/mL), and 336.0 U/mL (range: 7.0-1400.0 U/mL), respectively. Follow-up duration was less than 6 months for 11 patients and more than 6 months for 7 patients. At the time of the draft of this article, the mean survival of the patients included in the study was 185 days (range: 62-398 days).

CONCLUSION

Percutaneous radiofrequency ablation of locally advanced adenocarcinoma has a high technical success rate and is effective in cytoreduction both at imaging and laboratory controls.

Imaging in pancreatic disease

Pancreatic diseases, chronic pancreatitis, pancreatic cancer and diabetes mellitus, taken together, occur in >10% of the world population. Pancreatic diseases, as with other diseases, benefit from early intervention and appropriate diagnosis. Although imaging technologies have given clinicians an unprecedented toolbox to aid in clinical decision-making, advances in these technologies and development of molecular-based diagnostic tools could enable physicians to identify diseases at an even earlier stage and, thereby, improve patient outcomes. In this Review, we discuss and identify gaps in the use of imaging techniques for the early detection and appropriate treatment stratification of various pancreatic diseases, including diabetes mellitus, acute and chronic pancreatitis and pancreatic cancer. Imaging techniques discussed are MRI, CT, PET and ultrasonography. Additionally, the identification of new molecular targets for imaging and the development of contrast agents that are able to give molecular information in noninvasive radionuclear imaging and ultrasonography are emerging areas of innovation that could lead to increased diagnostic accuracy and improved patient outcomes.

Percutaneous ablation of pancreatic cancer

Pancreatic ductal adenocarcinoma is a highly aggressive tumor with an overall 5-year survival rate of less than 5%. Prognosis and treatment depend on whether the tumor is resectable or not, which mostly depends on how quickly the diagnosis is made. Chemotherapy and radiotherapy can be both used in cases of non-resectable pancreatic cancer. In cases of pancreatic neoplasm that is locally advanced, non-resectable, but non-metastatic, it is possible to apply percutaneous treatments that are able to induce tumor cytoreduction. The aim of this article will be to describe the multiple currently available treatment techniques (radiofrequency ablation, microwave ablation, cryoablation, and irreversible electroporation), their results, and their possible complications, with the aid of a literature review.

The endoscopist's role in the diagnosis and management of pancreatic cancer

Pancreatic cancer remains one of the most lethal malignancies with little improvement in survival over the past several decades in spite of advances in imaging, risk factor identification, surgical technique and chemotherapy. This disappointing outcome is mainly due to failures to make an early diagnosis. In fact, the majority of the patients present with inoperable advanced stages of the disease. Though some of the new tumor markers are promising, we are still in search of the one that has a high sensitivity and accuracy, yet is inexpensive and easy to obtain. The paradigm of management has shifted from up-front surgery followed by adjuvant chemotherapy to neoadjuvant chemoradiation followed by surgery, especially for borderline resectable cancers and even for some resectable cancers. In this article, we will critically assess the limitations of tumor markers and review the advancements in endoscopic techniques in the management of pancreatic cancer.

Comparison of Multidetector CT and Gadobutrol-Enhanced MR Imaging for Evaluation of Small, Solid Pancreatic Lesions

OBJECTIVE

To compare multidetector computed tomography (MDCT) and MRI for lesion conspicuity, as well as the detection and characterization of small solid pancreatic lesions (SPLs).

MATERIALS AND METHODS

193 patients with small SPLs (< 3 cm) and 52 patients with normal pancreas who underwent both multiphasic MDCT and gadobutrol-enhanced MRI were included in our study. Two radiologists blinded to the pathologic diagnoses independently reviewed those images, and determined the detection of "SPL per se" and "SPL in consideration of secondary features", the lesion conspicuity, the probability of pancreatic ductal adenocarcinoma (PDAC), and the most likely specific diagnosis.

RESULTS

The sensitivity of MRI for "detection of SPL per se" was significantly higher than that of CT in both reviewers: 92.7% (179/193) and 97.9% (189/193), respectively, for reviewer 1 (p = 0.031) and 90.7% (175/193) and 99.5% (192/193), respectively, for reviewer 2 (p < 0.001). In addition, MRI provided better lesion conspicuity than MDCT for both reviewers (p < 0.001). However, CT and MRI did not show significant difference in sensitivity for "detection of SPL in consideration of secondary features", specificity for SPL detection, and differentiation of PDAC vs. non-PDAC (p > 0.05). The accuracies of CT and MRI for making a specific diagnosis were as follows: 85.7% (210/245) vs. 86.9% (213/245), respectively, for reviewer 1 (p = 0.736), and 91.8% (225/245) vs. 93.5% (229/245), respectively, for reviewer 2 (p = 0.454).

CONCLUSION

MRI showed better lesion conspicuity than MDCT, but did not show significantly different diagnostic performance compared with MDCT for detecting and characterizing small SPLs.

Uncommon presentations of common pancreatic neoplasms: a pictorial essay

Pancreatic neoplasms are a wide group of solid and cystic lesions with different and often characteristic imaging features, clinical presentations, and management. Among solid tumors, ductal adenocarcinoma is the most common: it arises from exocrine pancreas, comprises about 90% of all pancreatic neoplasms, and generally has a bad prognosis; its therapeutic management must be multidisciplinary, involving surgeons, oncologists, gastroenterologists, radiologists, and radiotherapists. The second most common solid pancreatic neoplasms are neuroendocrine tumors: they can be divided into functioning or non-functioning and present different degrees of malignancy. Cystic pancreatic neoplasms comprise serous neoplasms, which are almost always benign, mucinous cystic neoplasms and intraductal papillary mucinous neoplasms, which can vary from benign to frankly malignant lesions, and solid pseudopapillary tumors. Other pancreatic neoplasms, such as lymphoma, metastases, or pancreatoblastoma, are rarely seen in clinical practice and have different and sometimes controversial managements. Rare clinical presentations and imaging appearance of the most common pancreatic neoplasms, both solid and cystic, are more frequently seen and clinically relevant than rare pancreatic tumors; their pathologic and radiologic appearances must be known to improve their management. The purpose of this paper is to present some rare or uncommon clinical and radiological presentations of common pancreatic neoplasms providing examples of multi-modality imaging approach with pathologic correlations, thus describing the histopathological bases that can explain the peculiar imaging features, in order to avoid relevant misdiagnosis and to improve lesion management.

Exosomes: potential for early detection in pancreatic cancer

Progress in the treatment of patients with pancreatic cancer at earlier stages has motivated research in identifying novel noninvasive or minimally invasive biomarkers for early detection. Exosomes, which contain bioactive molecules (such as proteins, RNAs and lipids), are membrane-structured nanovesicles that are secreted from living cells and are found in human body fluids. As functional mediators, exosomes play key roles in cell-cell communications, regulating diverse biological processes. Here we aim to examine recent findings in the potential diagnostic value of serum exosomes in pancreatic cancer.

Liver Contrast-Enhanced Ultrasound Improves Detection of Liver Metastases in Patients with Pancreatic or Periampullary Cancer

The aim of this study is to provide a diagnostic performance evaluation of contrast-enhanced ultrasonography (CEUS) in detecting liver metastases in patients with suspected of pancreatic or periampullary cancer. Computed tomography (CT) is often insufficient for detection of liver metastases, but their presence plays a crucial role in the choice of therapy. Eighty-nine patients with suspected pancreatic or periampullary cancer were included in this prospective study with retrospective analysis. Patients underwent an abdominal CT and CEUS. Fifteen patients had liver metastases. The CT sensitivity was 73.3% (11/15), the specificity 93.2% (69/74), the positive predictive value (PPV) 68.8% (11/16) and the negative predictive value (NPV) 94.6% (69/73). Based on CEUS, the sensitivity was 80% (12/15), specificity 98.6% (73/74), PPV 92.3% (12/13) and NPV 96.1% (73/76). CEUS improved characterization of liver lesions in patients with suspected pancreatic or periampullary cancer compared with CT. CEUS can better detect benign liver lesions and distinguish false-positive or indeterminate CT results.

Pancreatic Solid and Cystic Neoplasms: Diagnostic Evaluation and Intervention

High-resolution imaging modalities, such as multi-detector computed tomography, MR imaging, and endoscopic ultrasound, are frequently used alone or in combination to characterize focal solid and cystic pancreatic neoplasms. Imaging in solid pancreatic neoplasms, typically adenocarcinoma and neuroendocrine tumors, is primarily used to detect and stage the extent of the tumor and to determine if complete surgical resection for cure is feasible. In cystic pancreatic masses, imaging aims to differentiate benign nonmucinous cystic lesions from potentially or frankly malignant mucin-producing cysts. Several noninvasive and invasive treatment options can be performed if surgical resection is not possible or contraindicated.

Early detection of pancreatic cancer

Pancreatic adenocarcinoma is a low-incident but highly mortal disease. It accounts for only 3% of estimated new cancer cases each year but is currently the fourth common cause of cancer mortality. By 2030, it is expected to be the 2(nd) leading cause of cancer death. There is a clear need to diagnose and classify pancreatic cancer at earlier stages in order to give patients the best chance at a definitive cure through surgery. Three precursor lesions that distinctly lead to pancreatic adenocarcinoma have been identified, and we have increasing understanding the non-genetic and genetic risk factors for the disease. With increased understanding about the risk factors, the familial patters, and associated accumulation of genetic mutations involved in pancreatic cancer, we know that there are mutations that occur early in the development of pancreatic cancer and that improved genetic risk-based strategies in screening for pancreatic cancer may be possible and successful at saving or prolonging lives. The remaining challenge is that current standards for diagnosing pancreatic cancer remain too invasive and too costly for widespread screening for pancreatic cancer. Furthermore, the promises of noninvasive methods of detection such as blood, saliva, and stool remain underdeveloped or lack robust testing. However, significant progress has been made, and we are drawing closer to a strategy for the screening and early detection of pancreatic cancer.

Anatomical, Physiological, and Molecular Imaging for Pancreatic Cancer: Current Clinical Use and Future Implications

Pancreatic adenocarcinoma is one of the deadliest human malignancies. Early detection is difficult and effective treatment is limited. Verifying the presence of micrometastatic dissemination and vessel invasion remains elusive, limiting radiological staging once this diagnosis is made. Diagnostic imaging provides independent tools to evaluate and characterize the biologic behavior of pancreatic cancer. Conventional anatomic imaging alone with either CT or MRI yields useful information on organ involvement but is limited in providing molecular and physiological information. Molecular imaging techniques such as PET or MRS provide information on metabolic and signaling pathways. Advanced MR sequences that target physiological parameters expand imaging options to characterize these tumors. By considering the parametric data from these three imaging approaches (anatomic, molecular, and physiological) we can better define specific tumor signatures. Such parametric characterization can provide insight into tumor metabolism, cellular density, protein expression, focal perfusion, and vascular permeability of these tumors. Radiogenomics research has already demonstrated ability to obtain information about cancer's genotype and phenotype; this is without invasive procedures or surgery. Further advances in these areas of experimental imaging hold promise to enable future clinical advances in detection and therapy of pancreatic cancer.

Automated pancreatic cyst screening using natural language processing: a new tool in the early detection of pancreatic cancer

INTRODUCTION

As many as 3% of computed tomography (CT) scans detect pancreatic cysts. Because pancreatic cysts are incidental, ubiquitous and poorly understood, follow-up is often not performed. Pancreatic cysts may have a significant malignant potential and their identification represents a 'window of opportunity' for the early detection of pancreatic cancer. The purpose of this study was to implement an automated Natural Language Processing (NLP)-based pancreatic cyst identification system.

METHOD

A multidisciplinary team was assembled. NLP-based identification algorithms were developed based on key words commonly used by physicians to describe pancreatic cysts and programmed for automated search of electronic medical records. A pilot study was conducted prospectively in a single institution.

RESULTS

From March to September 2013, 566,233 reports belonging to 50,669 patients were analysed. The mean number of patients reported with a pancreatic cyst was 88/month (range 78-98). The mean sensitivity and specificity were 99.9% and 98.8%, respectively.

CONCLUSION

NLP is an effective tool to automatically identify patients with pancreatic cysts based on electronic medical records (EMR). This highly accurate system can help capture patients 'at-risk' of pancreatic cancer in a registry.

Pancreatic cancer: diagnosis and treatments

Pancreatic cancer is one of the deadliest cancers, with exceptionally high mortality. Despite the relatively low incidence rate (10th), it is the fourth leading cause of cancer-related deaths in most developed countries. To improve the early diagnosis of pancreatic cancer and strengthen the standardized comprehensive treatment are still the main focus of pancreatic cancer research. Here, we summarized the rapid developments in the diagnosis and treatments of pancreatic cancer. Regarding diagnosis, we reviewed advances in medical imaging technology, tumor markers, molecular biology (e.g., gene mutation), and proteomics. Moreover, great progress has also been made in the treatments of this disease, including surgical resection, chemotherapy, targeted radiotherapy, targeted minimally invasive treatment, and molecular targeted therapy. Therefore, we also recapitulated the development, advantages, and disadvantages of each of the treatment methods in this review.

Adult bile duct strictures: role of MR imaging and MR cholangiopancreatography in characterization

Bile duct strictures in adults are secondary to a wide spectrum of benign and malignant pathologic conditions. Benign causes of bile duct strictures include iatrogenic causes, acute or chronic pancreatitis, choledocholithiasis, primary sclerosing cholangitis, IgG4-related sclerosing cholangitis, liver transplantation, recurrent pyogenic cholangitis, Mirizzi syndrome, acquired immunodeficiency syndrome cholangiopathy, and sphincter of Oddi dysfunction. Malignant causes include cholangiocarcinoma, pancreatic adenocarcinoma, and periampullary carcinomas. Rare causes include biliary inflammatory pseudotumor, gallbladder carcinoma, hepatocellular carcinoma, metastases to bile ducts, and extrinsic bile duct compression secondary to periportal or peripancreatic lymphadenopathy. Contrast material-enhanced magnetic resonance (MR) imaging with MR cholangiopancreatography is extremely helpful in the noninvasive evaluation of patients with obstructive jaundice, an obstructive pattern of liver function, or incidentally detected biliary duct dilatation. Some of these conditions may show characteristic findings at MR imaging-MR cholangiopancreatography that help in making a definitive diagnosis. Although endoscopic retrograde cholangiopancreatography with tissue biopsy or surgery is needed for the definitive diagnosis of many of these strictures, certain MR imaging characteristics of the narrowed segment (eg, thickened wall, long-segment involvement, asymmetry, indistinct outer margin, luminal irregularity, hyperenhancement relative to the liver parenchyma) may favor a malignant cause. Awareness of the various causes of bile duct strictures in adults and familiarity with their appearances at MR imaging-MR cholangiopancreatography are important for accurate diagnosis and optimal patient management.

Pancreatic intraductal papillary mucinous neoplasm--where is the challenge?

Cystic lesions of the pancreas are increasingly recognized due to the widespread use of modern abdominal imaging technologies. The majority of these lesions display pseudocysts and mucinous cystic neoplasms. In contrast to pseudocysts, it is well established that mucinous cystic neoplasms of the pancreas exhibit a significant potential for malignant transformation over time. Among mucinous cystic tumors, the most frequently observed entity is pancreatic intraductal papillary mucinous neoplasm (IPMN). IPMNs are characterized by cystic dilation of pancreatic ducts and the production of mucus and by an adenoma-carcinoma sequence eventually culminating in invasive carcinoma in some patients. Due to the high risk of harboring malignancy, there is international consensus that IPMNs with involvement of the main pancreatic duct should be recommended for surgical resection. To date, the indication for surgery of branch-duct IPMNs is controversially discussed because of the overall lower risk of malignant transformation compared to main-duct IPMNs. Particularly for small and asymptomatic side-branch IPMNs, the indication for surgical resection remains challenging. In addition to the international consensus guidelines, a number of potential preoperative features predicting malignant transformation have been discussed recently. Moreover, novel surgical pancreatic parenchyma-sparing techniques such as enucleations or segmental pancreatic resections have been reported in order to treat IPMNs. The present article aims to demonstrate the current scientific knowledge in this field and to highlight the current controversy.

Screening for pancreatic cancer

Even with improved cancer care generally, the incidence and death rate is increasing for pancreatic cancer. Concern exists that a further increase in deaths caused by pancreatic cancer will be seen as other causes of death, such as heart disease and other cancers, decline. Critical exploration of screening high-risk patients as a tool to reduce deaths from pancreatic cancer should be considered. Technological advances and improved understanding of pancreatic cancer biology provides an opportunity to identify and test a panel of early detection biomarkers easily, accurately, and inexpensively measured in blood, urine, stool, or saliva samples. These biomarkers may have additional usefulness in staging, stratification for treatment, establishing prognosis, and assessing response to therapy in this disease. Screening may prove to be one of several strategies to improve outcomes in a disease that has otherwise been difficult to defeat.

Sensitivity of EUS and ERCP Endoscopic Procedures in the Detection of Pancreatic Cancer During Preoperative Staging Correlated with CT and CT Angiography Imaging Methods

The goal:

The goal of this work was to give advantage to EUS as endoscopic method in diagnosis and following therapeutic treatment of pancreatic cancer in relation to radiological methods of CT and CTA.

Material and Methods:

The study included 49 patients, 20 women and 29 men hospitalized at the Clinic for gastroenterohepatology, due to suspicion on pancreatic cancer during observed 2 years period. All cancers were histologically and cytologically confirmed. The patients underwent ERCP as a mandatory part of staging and all patients underwent endoscopic ultrasound as well as CT or CT angiography.

Results:

Testing of differences was carried out using Fisher’s exact test in open-source software R. The following characteristics were tested: involvement of the blood vessels, lymph nodes, metastases, tumor size and duodenum infiltration. Results showed statistically significant difference at the 0.05 level for EUS, CT and CT angiography. Risk ratio showed that EUS is less effective in detecting infiltration of blood vessels within a malignant process then CTA where RR=0.52, CI 0.2–1.38, p-value=0.33. EUS and CTA are equal in the diagnosis of enlarged lymph nodes affected by malignancy where RR=1.3, CI 0.75–1.42, p-value=0.09. Comparison according to distant metastases showed that EUS is less effective compared to CT in approximately 30% of cases. In the diagnosis of duodenal infiltration EUS is in 5% of cases less accurate than the CT with the RR=0.95, CI 0.27–3.32, p-value=0.76, but the CTA method is more efficient because the comparison of EUS and CTA showed RR=12.52, CI 0.2–1.38, p-value=0.33. EUS as a diagnostic method is dominant in determining the size of malignant lesions located in the pancreas as compared to CT and CTA.

Conclusion:

EUS as endoscopic method compared to CT and CTA is one of the more invasive methods of examination but due to its ability to be performed immediately, to locate a changes smaller than 5 mm and the target biopsy option, to measure the change and that in many cases determine the relationship of malignant lesions with blood vessels, along with visualization of the surrounding lymph nodes and metastases in neighboring organs, we may give this method an advantage over other methods in the preoperative staging of patients with pancreatic cancer.