Peripancreatic Vessels Research Articles

Inter-reader agreement of pancreatic adenocarcinoma resectability assessment with photon counting versus energy integrating detector CT.

To compare the inter-reader agreement of pancreatic adenocarcinoma resectability assessment at pancreatic protocol photon-counting CT (PCCT) with conventional energy-integrating detector CT (EID-CT). A retrospective single institution database search identified all contrast-enhanced pancreatic mass protocol abdominal CT performed at an outpatient facility with both a PCCT and EID-CT from 4/11/2022 to 10/30/2022. Patients without pancreatic adenocarcinoma were excluded. Four fellowship-trained abdominal radiologists, blinded to CT type, independently assessed vascular tumor involvement (uninvolved, abuts ≤ 180°, encases > 180°; celiac, superior mesenteric artery (SMA), common hepatic artery (CHA), superior mesenteric vein (SMV), main portal vein), the presence/absence of metastases, overall tumor resectability (resectable, borderline resectable, locally advanced, metastatic), and diagnostic confidence. Fleiss's kappa was used to calculate inter-reader agreement. CTDIvol was recorded. Radiation dose metrics were compared with a two-sample t-test. A p < .05 indicated statistical significance. 145 patients (71 men, mean[SD] age: 66[9] years) were included. There was substantial inter-reader agreement, for celiac artery, SMA, and SMV involvement at PCCT (kappa = 0.61-0.69) versus moderate agreement at EID-CT (kappa = 0.56-0.59). CHA had substantial inter-reader agreement at both PCCT (kappa = 0.67) and EIDCT (kappa = 0.70). For metastasis identification, radiologists had substantial inter-reader agreement at PCCT (kappa = 0.78) versus moderate agreement at EID-CT (kappa = 0.56). CTDIvol for PCCT and EID-CT were 16.9[7.4]mGy and 29.8[26.6]mGy, respectively (p < .001). There was substantial inter-reader agreement for involvement of 4/5 major peripancreatic vessels (celiac artery, SMA, CHA, and SMV) at PCCT compared with 2/5 for EID-CT. PCCT also afforded substantial inter-reader agreement for metastasis detection versus moderate agreement at EID-CT with statistically significant radiation dose reduction.

Automated peripancreatic vessel segmentation and labeling based on iterative trunk growth and weakly supervised mechanism

Peripancreatic vessel segmentation and anatomical labeling are pivotal aspects in aiding surgical planning and prognosis for patients with pancreatic tumors. Nevertheless, prevailing techniques often fall short in achieving satisfactory segmentation performance for the peripancreatic vein (PPV), leading to predictions characterized by poor integrity and connectivity. Besides, unsupervised labeling algorithms usually cannot deal with complex anatomical variation while fully supervised methods require a large number of voxel-wise annotations for training, which is very labor-intensive and time-consuming. To address these two problems, we propose an Automated Peripancreatic vEssel Segmentation and lAbeling (APESA) framework, to not only highly improve the segmentation performance for PPV, but also efficiently identify the peripancreatic artery (PPA) branches. There are two core modules in our proposed APESA framework: iterative trunk growth module (ITGM) for vein segmentation and weakly supervised labeling mechanism (WSLM) for artery labeling. The ITGM is composed of a series of iterative submodules, each of which chooses the largest connected component of the previous PPV segmentation as the trunk of a tree structure, seeks for the potential missing branches around the trunk by our designed branch proposal network, and facilitates trunk growth under the connectivity constraint. The WSLM incorporates the rule-based pseudo label generation with less expert participation, an anatomical labeling network to learn the branch distribution voxel by voxel, and adaptive radius-based postprocessing to refine the branch structures of the labeling predictions. Our achieved Dice of 94.01% for PPV segmentation on our collected dataset represents an approximately 10% accuracy improvement compared to state-of-the-art methods. Additionally, we attained a Dice of 97.01% for PPA segmentation and competitive labeling performance for PPA labeling compared to prior works. Our source codes will be publicly available at https://github.com/ZouLiwen-1999/APESA.

A Generalizable Causal-Invariance-Driven Segmentation Model for Peripancreatic Vessels.

Segmenting peripancreatic vessels in CT, including the superior mesenteric artery (SMA), the coeliac artery (CA), and the partial portal venous system (PPVS), is crucial for preoperative resectability analysis in pancreatic cancer. However, the clinical applicability of vessel segmentation methods is impeded by the low generalizability on multi-center data, mainly attributed to the wide variations in image appearance, namely the spurious correlation factor. Therefore, we propose a causal-invariance-driven generalizable segmentation model for peripancreatic vessels. It incorporates interventions at both image and feature levels to guide the model to capture causal information by enforcing consistency across datasets, thus enhancing the generalization performance. Specifically, firstly, a contrast-driven image intervention strategy is proposed to construct image-level interventions by generating images with various contrast-related appearances and seeking invariant causal features. Secondly, the feature intervention strategy is designed, where various patterns of feature bias across different centers are simulated to pursue invariant prediction. The proposed model achieved high DSC scores (79.69%, 82.62%, and 83.10%) for the three vessels on a cross-validation set containing 134 cases. Its generalizability was further confirmed on three independent test sets of 233 cases. Overall, the proposed method provides an accurate and generalizable segmentation model for peripancreatic vessels and offers a promising paradigm for increasing the generalizability of segmentation models from a causality perspective. Our source codes will be released at https://github.com/SJTUBME-QianLab/PC_VesselSeg.

Recurrent upper gastrointestinal bleeding in chronic pancreatitis since childhood: a case report

Chronic pancreatitis is a progressive inflammatory disease of the pancreas. Causes of gastrointestinal (GI) bleeding in chronic pancreatitis are bleeding into the pseudocyst, pseudoaneurysm of peripancreatic vessels, and thrombosis of portal vein and splenic vein. We are presenting a rare case presentation of recurrent GI bleed in chronic pancreatitis since childhood and its management. A seventeen-year-old female patient presented with recurrent attacks of upper abdominal pain, hematemesis, bleeding per rectum, and melena since 1 month of age. She was diagnosed with a case of chronic calcific pancreatitis with pseudoaneurysm of common hepatic artery, and portal vein thrombosis with splenomegaly at the age of 2 years. She underwent angioembolization of the common hepatic artery pseudoaneurysm at the age of 2 years. However, she continued to have recurrent episodes of upper GI bleeding which required multiple hospital admissions and blood transfusions in the past. Contrast-enhanced computed tomography of abdomen was suggestive of chronic calcific pancreatitis with status post coil embolization of common hepatic, gastroduodenal, and proper hepatic arteries. She underwent modified Frey’s procedure in view of recurrent symptoms. Currently, the patient is doing well after 18 months of follow-up, with no further episodes of GI bleed. Angioembolization or surgical ligation of pseudoaneurysm of involved vessels in chronic pancreatitis can control GI bleed. However, in cases where the source of bleeding is not localized by imaging/ endoscopy, drainage of pseudocyst or local resection of pancreatic tissue can reduce inflammation in and around the pancreas and prevent further GI bleed in chronic pancreatitis.

Inframesocolic main pancreatic vessels-first approach for minimally invasive radical antegrade modular pancreaticosplenectomy (RAMPS): technical description and first experience.

Radical modular antegrade pancreaticosplenectomy (RAMPS) improves posterior tumor-free margins during resections of pancreatic neoplasia involving the body or tail. However, minimally invasive RAMPS is technically challenging and has been reported seldom. We present for the first time a minimally invasive RAMPS technique with an innovative approach providing early dissection and control of the main peripancreatic vessels from an inframesocolic embryonal window, suitable for laparoscopy and robotics. Minimally invasive RAMPS with inframesocolic main pancreatic vessels-first approach was performed at the Tricase Hospital (Italy) from May 2017 to April 2022 in 11 consecutive patients with neoplastic lesions of the pancreas (8 laparoscopic RAMPS and 3 robotic RAMPS). Among the laparoscopic cases, 1 included a portal vein tangential resection and 1 a celiac artery resection (modified Appleby procedure). There were no conversions, no Clavien-Dindo complications > 2, all resections' margins were tumor free, and no 90-day mortality.

Validation of a Resectability Scoring System for Prediction of Pancreatic Adenocarcinoma Surgical Outcomes.

The most used pancreatic cancer (PC) resectability criteria are descriptive in nature or based solely on dichotomous degree of involvement (< 180° or > 180°) of vessels, which allows for a high degree of subjectivity and inconsistency. Radiographic measurements of the circumferential degree and length of tumor contact with major peripancreatic vessels were retrospectively obtained from pre-treatment multi-detector computed tomography (MDCT) images from PC patients treated between 2001 and 2015 at two large academic institutions. Arterial and venous scores were calculated for each patient, then tested for a correlation with tumor resection and R0 resection. The analysis included 466 patients. Arterial and venous scores were highly predictive of resection and R0 resection in both the training (n = 294) and validation (n = 172) cohorts. A recursive partitioning tree based on arterial and venous score cutoffs developed with the training cohort was able to stratify patients of the validation cohort into discrete groups with distinct resectability probabilities. A refined recursive partitioning tree composed of three resectability groups was generated, with probabilities of resection and R0 resection of respectively 94 and 73% for group A, 61 and 35% for group B, and 4 and 2% for group C. This resectability scoring system (RSS) was highly prognostic, predicting median overall survival times of 27, 18.9, and 13.5 months respectively for patients in RSS groups A, B, and C (p < 0.001). The proposed RSS was highly predictive of resection, R0 resection, and prognosis for patients with PC when tested against an external dataset.

Portal-mesenteric vein resection for pancreatic cancer: Results in par with the defined benchmark outcomes.

Patients with pancreatic cancer (PC), which may involve major peripancreatic vessels, have been generally excluded from surgery, as resection was deemed futile. The purpose of this study was to analyze the results of portomesenteric vein resection in borderline resectable or locally advanced PC. This study comprises the largest series of such patients in Greece. Investigator-initiated, retrospective, noncomparative study of patients with borderline resectable or locally advanced adenocarcinoma undergoing pancreatectomy en-block with portal and/or superior mesenteric vein resection in a tertiary referral center in Greece between January 2014 and October 2021. Follow-up was complete up to December 2021. Operative and outcome measures were determined. Forty patients were included. Neoadjuvant therapy was administered to only 58% and was associated with smaller tumor size (median: 2.9 cm vs. 4.2 cm, p = 0.004), but not with increased survival. Though venous wall infiltration was present in 55%, it was not associated with tumor size, or Eastern Cooperative Oncology Group (ECOG) status. Resection was extensive: a median of 27 LNs were retrieved, R0 resection rate (≥1 mm) was 87%, and median length of resected vein segments was 3 cm, requiring interposition grafts in 40% (polytetrafluoroethylene). Median ICU stay was 0 days and length of hospitalization 9 days. Postoperative mortality was 2.5%. Median follow-up was 46 months and median overall survival (OS) was 24 months. Two-, 3- and 5-year OS rates were 49%, 33%, and 22% respectively. All outcomes exceeded benchmark cutoffs. Lower ECOG status was positively correlated with longer survival (ECOG-0: 32 months, ECOG-1: 24 months, ECOG-2: 12 months, p = 0.02). This series of portomesenteric resection in borderline resectable or locally advanced PC demonstrated a median survival of 2 years, extending to 32 months in patients with good performance status, which meet or exceed current outcome benchmarks.

Three-dimensional simulation of the pancreatic parenchyma, pancreatic duct and vascular arrangement in pancreatic surgery using a deep learning algorithm.

Three-dimensional surgical simulation, already in use for hepatic surgery, can be used in pancreatic surgery. However, some problems still need to be overcome to achieve more precise pancreatic surgical simulation. The present study evaluates the performance of SYNAPSE VINCENT® (version 6.6, Fujifilm Medical Co., Ltd., Tokyo, Japan) in the semiautomated surgical simulation of the pancreatic parenchyma, pancreatic ducts, and peripancreatic vessels using an artificial intelligence (AI) engine designed with deep learning algorithms. One-hundred pancreatic cancer patients and a control group of 100 nonpancreatic cancer patients were enrolled. The evaluation methods for visualizing the extraction were compared using the Dice coefficient (DC). In the pancreatic cancer patients, tumor size, position, and stagewise correlations with the pancreatic parenchymal DC were analyzed. The relationship between the pancreatic duct diameter and the DC, and between the manually and AI-measured diameters of the pancreatic duct were analyzed. In the pancreatic cancer/control groups, the pancreatic parenchymal DC and pancreatic duct extraction were 0.83/0.86 and 0.84/0.77. The DC of the arteries (portal veins/veins) and associated sensitivity and specificity were 0.89/0.88 (0.89/0.88), 0.85/0.83 (0.85/0.82), and 0.82/0.81 (0.84/0.81), respectively. No correlations were observed between pancreatic parenchymal DC and tumor size, position, or stage. No correlation was observed between the pancreatic duct diameter and the DC. A positive correlation (r = 0.61, p<0.001) was observed between the manually and AI-measured diameters of the pancreatic duct. Extraction of the pancreatic parenchyma, pancreatic duct, and surrounding vessels with the SYNAPSE VINCENT® AI engine assumed to be useful as surgical simulation.

Dual-energy CT with virtual monoenergetic images and iodine maps improves tumor conspicuity in patients with pancreatic ductal adenocarcinoma

ObjectivesTo evaluate the value of monoenergetic images (MEI [+]) and iodine maps in dual-source dual-energy computed tomography (DECT) for assessing pancreatic ductal adenocarcinoma (PDAC), including the visually isoattenuating PDAC.Materials and methodsThis retrospective study included 75 PDAC patients, who underwent contrast-enhanced DECT examinations. Conventional polyenergetic image (PEI) and 40–80 keV MEI (+) (10-keV increments) were reconstructed. The tumor contrast, contrast-to-noise ratio (CNR) of the tumor and peripancreatic vessels, the signal-to-noise ratio (SNR) of the pancreas and tumor, and the tumor diameters were quantified. On iodine maps, the normalized iodine concentration (NIC) in the tumor and parenchyma was compared. For subjective analysis, two radiologists independently evaluated images on a 5-point scale.ResultsAll the quantitative parameters were maximized at 40-keV MEI (+) and decreased gradually with increasing energy. The tumor contrast, SNR of pancreas and CNRs in 40–60 keV MEI (+) were significantly higher than those in PEI (p < 0.05). For visually isoattenuating PDAC, 40–50 keV MEI (+) provided significantly higher tumor CNR compared to PEI (p < 0.05). The reproducibility in tumor measurements was highest in 40-keV MEI (+) between the two radiologists. The tumor and parenchyma NIC were 1.28 ± 0.65 and 3.38 ± 0.72 mg/mL, respectively (p < 0.001). 40–50 keV MEI (+) provided the highest subjective scores, compared to PEI (p < 0.001).ConclusionsLow-keV MEI (+) of DECT substantially improves the subjective and objective image quality and consistency of tumor measurements in patients with PDAC. Combining the low-keV MEI (+) and iodine maps may yield diagnostically adequate tumor conspicuity in visually isoattenuating PDAC.

Utility of Diffusion-Weighted MRI for Detection of Locally Recurrent Pancreatic Cancer After Surgical Resection.

BACKGROUND. Overlapping imaging findings between local tumor recurrence and postsurgical fibrosis represent a major clinical challenge after pancreatic ductal adeno-carcinoma (PDAC) resection. OBJECTIVE. The purpose of this study was to compare the diagnostic performance of MRI with and without DWI for differentiating locally recurrent tumor and postsurgical fibrosis after PDAC resection. METHODS. This retrospective study included 66 patients (35 men, 31 women; mean age, 60.5 years) who underwent PDAC resection between January 2009 and March 2016, postoperative surveillance CT showing a soft-tissue lesion at the operative site or at the site of peripancreatic vessels, and subsequent MRI with DWI for further evaluation. CT at least 6 months after MRI served as the reference standard, with increase in size of the soft tissue by 5 mm or more differentiating locally recurrent tumor (n = 26) and postsurgical fibrosis (n = 40). Two observers in consensus evaluated MRI characteristics of the soft-tissue lesions. Two additional observers independently reviewed MRI examinations in two separate sessions (conventional MRI alone vs MRI with DWI), recording likelihood of recurrent tumor using a 1-5 scale. ROC analysis was performed, considering scores of 4 or 5 as positive. RESULTS. Subjective diffusion restriction was more common in locally recurrent tumor than postsurgical fibrosis (88.5% vs 25.0%, p = .01). Median ADC was lower for locally recurrent tumor than postsurgical fibrosis (1.3 vs 1.7 × 10-3 mm2/s, p < .001). For both observers, MRI with DWI in comparison with conventional MRI alone showed higher AUC for diagnosis of locally recurrent tumor (observer 1: 0.805 vs 0.707, p = .048; observer 2: 0.898 vs 0.637, p < .001) and higher sensitivity (observer 1: 88.5% vs 61.5%, p = .008; observer 2: 84.6% vs 42.3%, p = .001) but no difference in specificity (observer 1: 72.5% vs 80.0%, p = .08; observer 2, 95.0% vs 85.0%, p = .10). Interobserver agreement was moderate for conventional MRI (κ = 0.41) and good for conventional MRI with DWI (κ = 0.62). CONCLUSION. The addition of DWI to conventional MRI improves the differentiation of locally recurrent tumor and postsurgical fibrosis after PDAC resection, primarily because of improved sensitivity for recurrence. CLINICAL IMPACT. The findings indicate a potential role for MRI with DWI in surveillance protocols after PDAC resection.

Better Therapy for Pancreatic Cancer through More Radical Surgery?

Despite advances in the treatment of pancreatic cancer, the survival of affected patients remains limited. A more radical surgical therapy could help to improve the prognosis, in particular by reducing the local recurrence rate, which is around 45% in patients with resected pancreatic cancer. In addition, patients with oligometastatic pancreatic cancer could also benefit from a more radical indication for surgery.Based on an analysis of the literature, important principles of pancreatic cancer surgery were examined.Even if even more radical surgical approaches such as an "extended" lymphadenectomy or a standard complete pancreatectomy do not bring any survival advantage, complete resection of the tumour (R0), a thorough locoregional lymphadenectomy and an adequate radical dissection in the area of the peripancreatic vessels including periarterial nerve plexuses should be the standard of pancreatic carcinoma resections. Whenever necessary to achieve an R0 resection, resections of the pancreas have to be extended, as well as additional venous vascular resections and multivisceral resections had to be performed. Simultaneous arterial vascular resections as part of pancreatic resections as well as surgical resections in oligometastatic patients should, however, be reserved for selected patients. These aspects of the surgical technique in pancreatic carcinoma mentioned above must not be neglected from the point of view of an "existing limited prognosis". On the contrary, they form the absolutely necessary basis in order to achieve good survival results in combination with system therapy. However, it may always be necessary to adapt these standards according to the age, comorbidities and wishes of the patient.

Ablative Radiotherapy (ART) for Locally Advanced Pancreatic Cancer (LAPC): Toward a New Paradigm?

Locally advanced pancreatic cancer (LAPC) represents a major urgency in oncology. Due to the massive involvement of the peripancreatic vessels, a curative-intent surgery is generally precluded. Historically, LAPC has been an indication for palliative systemic therapy. In recent years, with the introduction of intensive multi-agent chemotherapy regimens and aggressive surgical approaches, the survival of LAPC patients has significantly improved. In this complex and rapidly evolving scenario, the role of radiotherapy is still debated. The use of standard-dose conventional fractionated radiotherapy in LAPC has led to unsatisfactory oncological outcomes. However, technological advances in radiation therapy over recent years have definitively changed this paradigm. The use of ablative doses of radiotherapy, in association with image-guidance, respiratory organ-motion management, and adaptive protocols, has led to unprecedented results in terms of local control and survival. In this overview, principles, clinical applications, and current pitfalls of ablative radiotherapy (ART) as an emerging treatment option for LAPC are discussed.

English

Pleural effusions in acute pancreatitis are usually small, occasionally bloody, characterized by high amylase, protein levels.1 Majority of pleural effusions secondary to pancreatitis are left-sided (68 %) or bilateral (22 %) and only 10 % are right sided. Hemosuccus pancreaticus (HP) is caused by rupture of aneurysm of a peripancreatic vessel into pancreatic duct or pancreatic pseudocyst in the context of pancreatitis. HP is the least frequent cause of upper gastrointestinal bleeding (1 / 1500), but can lead to potentially life threatening2 massive gastrointestinal bleeding. Hemosuccus pancreaticus is defined as bleeding from the ampulla of Vater via pancreatic duct. It is due to a bleeding source in the pancreas, pancreatic duct, or structures adjacent to the pancreas, like the gastroduodenal and splenic artery. The most common cause is a pseudoaneurysm of peripancreatic arteries due to acute or chronic pancreatitis.3,4 Other rare causes are trauma,5 rupture of a true aneurysm,6 pancreatic tumours,7 arteriovenous (AV) malformations,8 endoscopic ultrasoundguided fine needle aspiration from pancreatic cyst9 etc.

Incidence and Contemporary Management of Delayed Bleeding Following Pancreaticoduodenectomy.

Delayed bleeding after pancreaticoduodenectomy (PD) is a life-threatening complication. However, the optimal management remains unclear. We summarize our experience of the management of delayed bleeding after PD and define the outcomes associated with different types of management. All patients who underwent a PD between January 1987 and June 2020 at Johns Hopkins University were retrospectively reviewed. Delayed bleeding was defined as bleeding on or after postoperative day 5 following PD. Incidence, outcomes, and trends were reported. Among the 6201 patients that underwent PD, delayed bleeding occurred in 130 (2.1%) at a median of 12days (IQR: 9, 24) postoperation. The pattern of bleeding was classified as intraluminal (51.5%), extraluminal (40.8%), and mixed (7.7%). A clinically relevant postoperative pancreatic fistula and an intraabdominal abscess preceded the delayed bleeding in 43.1% and 31.5% of cases, respectively. Arterial pseudoaneurysm or bleeding from peripancreatic vessels was the most common reason (54.6%) with the gastroduodenal artery being the most common source (18.5%). Endoscopy, angiography, and reoperation were performed as a first-line approach in 35.4%, 52.3%, and 6.2% of patients, respectively. The overall mortality was 16.2% and decreased over the study period (p < 0.01). Delayed bleeding following PD remains a life-threatening complication. The most common location of delayed bleeding is from the gastroduodenal artery. Angiography with embolization should be the initial approach for urgent bleeding with surgical re-exploration reserved for unstable patients or failed control of bleeding after interventional angiography or endoscopy.

Hemosuccus Pancreaticus Following Acute Pancreatitis in a 12-years-old Boy Secondary to Pancreatic Pseudoaneurysm Treated With Endovascular Coil Embolization

Hemosuccus pancreaticus is a very rare cause of upper gastrointestinal bleeding in children. It is defined as bleeding from the pancreatic or peripancreatic vessels into the main pancreatic duct and may be life-threatening. We present the case of a 12-year-old boy with hematemesis and severe anemia that developed following an episode of acute pancreatitis. Upper endoscopy did not reveal a bleeding source. An endoscopic retrograde cholangiopancreatography performed for the evaluation of common bile duct obstruction identified bleeding from the pancreatic duct. Subsequently, the bleeding source, a pseudoaneurysm of the splenic artery, was identified by conventional angiography and occluded with coil embolization. The diagnosis of hemosuccus pancreaticus may be difficult in children due to rare occurrence and the unusual anatomical site; hence, a high index of suspicion is needed in a patient with a history of pancreatitis who presents with intermittent upper gastrointestinal bleeding and normal upper endoscopy.

A Crowdsourcing Challenge for the Development of Artificial Intelligence Algorithms for Automated Identification and Delineation of Pancreatic Cancer Primary Tumors

To develop a crowdsourced artificial intelligence computational algorithm to accurately identify and delineate pancreatic cancer (PC) primary tumors and major peripancreatic vessels on high-resolution CT images.After IRB approval, a well-curated data set of 243 diagnostic pancreatic-protocol high-resolution CT scans of patients diagnosed with PC was prepared. A data science marathon competition was then hosted online by a third-party company between December 2020 and January 2021. The full data set was randomly partitioned into training, validation and hold-out (scoring) data sets. Contestants were provided a training dataset containing [de-identified files from a high-resolution IV contrast-enhanced CT DICOM image set; de-identified DICOM metadata; de-identified RT structure set file with contours of the tumor and superior mesenteric artery (SMA), celiac axis/common hepatic artery continuum (CA/CHA), and superior mesenteric vein/portal vein continuum (SMV/PV)], along with a smaller validation data set with CT scans without contours to test their trained algorithms. Provisional scores were assigned using the validation data set throughout the competition. Final scoring of submitted algorithms was based on the performance of the algorithms on a hold-out data set (unavailable for the contestants), matched against the expected ground truth data using an F1 scoring metric [2 * precision * recall / (precision + recall)], in which precision = TP / (TP + FP), and recall = TP / (TP + FN). TP is the area (measured in pixels) of the overlap of expected (ground truth delineation) and extracted (submitted algorithm) regions, FP is the area extracted but which does not belong to expected regions, FN is the area of the expected regions that is not covered by extracted regions. The above was calculated separately for the 4 structure types (tumor, SMA, CA/CHA, and SMV/PV), with a weighted average of the four F1 values, where the weight of the tumor was 7, and the weight of each of the vessels was 1. A final average for each contestant was scaled up to 0-100 range.In total, 337 algorithm solutions from 23 competitors were submitted. The winning algorithm achieved an average F1 score of 70.2. The F1 score ranged from 69.8 to 66.7 between the 2nd and 5th best solutions. The winning solution used a 3D-UNet model to develop a 3D semantic segmentation approach that was found to be significantly accurate on tumor and vessel delineation. A comparison between the winning solution and an ensemble between the 2nd to 5th place solutions showed that in 82% of cases, both the winning and the ensembled solution succeeded in achieving an F1 score > 60.A crowdsourced innovation challenge was successfully employed to generate artificial intelligence algorithms capable of accurately delineating pancreatic cancer on a diagnostic CT scan.

Safety of Irreversible Electroporation Ablation of the Pancreas.

To evaluate the safety of irreversible electroporation (IRE) on swine pancreatic tissue including its effects on peripancreatic vessels, bile ducts, and bowel. Eighteen Yorkshire pigs underwent IRE ablation of the pancreas successfully and without clinical complications. Contrast-enhanced computed tomography angiography and laboratory studies before the IRE ablation with follow-up computed tomography angiography, laboratory testing, and pathological examination up to 4 weeks postablation were performed. In a subset of cases, anatomic peripancreatic vessel narrowing was seen by 1 week postablation, persisting at 4 weeks postablation, without apparent functional impairment of blood flow. Laboratory studies revealed elevated amylase and lipase at 24 hours post-IRE, suggestive of acute pancreatitis, which normalized by 4 weeks post-IRE. There was extensive pancreatic tissue damage 24 hours after IRE with infiltration of immune cells, which was gradually replaced by fibrotic tissue. Ductal regeneration without loss of pancreatic acinar tissue and glandular function was observed at 1 and 4 weeks postablation. In our study, we demonstrated and confirmed the safety and minimal complications of IRE ablation in the pancreas and its surrounding vital structures. These results show the potential of IRE as an alternative treatment modality in patients with pancreatic cancer, especially those with locally advanced disease.

Pre-Operative MDCT Staging Predicts Mesopancreatic Fat Infiltration-A Novel Marker for Neoadjuvant Treatment?

Simple SummaryAfter the implementation of an internationally recognized histopathological protocol, the rate of complete resections of pancreatic-head cancers has dropped significantly. As recently discovered, the fat surrounding the pancreatic head is infiltrated in most of the patients suffering from pancreatic head cancer. This presumably contributed to the low rates of complete resections. Therefore, these patients show signs of borderline resectability and may benefit from a chemotherapy prior to surgery. The aim of this study was to re-analyze the preoperative CT scans and to correlate those with the histopathological results. We found that the existence of cancerous infiltration of the fat surrounding the pancreas can be predicted by preoperative CT scan and that this in turn can discriminate between patients receiving complete or incomplete resections. Hence, a new standardized radiographic protocol should be implemented and preoperative chemotherapy may be warranted for at risk patients. Summary: The rates of microscopic incomplete resections (R1/R0CRM+) in patients receiving standard pancreaticoduodenectomy for PDAC remain very high. One reason may be the reported high rates of mesopancreatic fat infiltration. In this large cohort study, we used available histopathological specimens of the retropancreatic fat and correlated high resolution CT-scans with the microscopic tumor infiltration of this area. We found that preoperative MDCT scans are suitable to detect cancerous infiltration of this mesopancreatic tissue and this, in turn, was a significant indicator for both incomplete surgical resection (R1/R0CRM+) and worse overall survival. These findings indicate that a neoadjuvant treatment in PDAC patients with CT-morphologically positive infiltration of the mesopancreas may result in better local control and thus improved resection rates. Mesopancreatic fat stranding should thus be considered in the decision for neoadjuvant therapy. Background: Due to the persistently high rates of R1 resections, neoadjuvant treatment and mesopancreatic excision (MPE) for ductal adenocarcinoma of the pancreatic head (hPDAC) have recently become a topic of interest. While radiographic cut-off for borderline resectability has been described, the necessary extent of surgery has not been established. It has not yet been elucidated whether pre-operative multi-detector computed tomography (MDCT) staging reliably predicts local mesopancreatic (MP) fat infiltration and tumor extension. Methods: Two hundred and forty two hPDAC patients that underwent MPE were analyzed. Radiographic re-evaluation was performed on (1) mesopancreatic fat stranding (MPS) and stranding to peripancreatic vessels, as well as (2) tumor diameter and anatomy, including contact to peripancreatic vessels (SMA, GDA, CHA, PV, SMV). Routinely resected mesopancreatic and perivascular (SMA and PV/SMV) tissue was histopathologically re-analyzed and histopathology correlated with radiographic findings. A logistic regression of survival was performed. Results: MDCT-predicted tumor diameter correlated with pathological T-stage, whereas presumed tumor contact and fat stranding to SMA and PV/SMV predicted and correlated with histological cancerous infiltration. Importantly, mesopancreatic fat stranding predicted MP cancerous infiltration. Positive MP infiltration was evident in over 78%. MPS and higher CT-predicted tumor diameter correlated with higher R1 resection rates. Patients with positive MP stranding had a significantly worse overall survival (p = 0.023). Conclusions: A detailed preoperative radiographic assessment can predict mesopancreatic infiltration and tumor morphology and should influence the decision for primary surgery, as well as the extent of surgery. To increase the rate of R0CRM− resections, MPS should be considered in the decision for neoadjuvant therapy.

Mesopancreatic excision for pancreatic ductal adenocarcinoma improves local disease control and survival

BackgroundSurvival in ductal adenocarcinoma of the pancreatic head (hPDAC) is poor. After implementation of the circumferential resection margin (CRM) into standard histopathological evaluation, the margin negative resection rate has drastically dropped. However, the impact of surgical radicality on survival and the influence of malignant infiltration of the mesopancreatic fat remains unclear. At our institution, a standardized dissection of the mesopancreatic lamina and peri-pancreatic vessels are obligatory components of radical pancreatoduodenectomy. The aim of our study was to histopathologically analyze mesopancreatic tumor infiltration and the influence of CRM-evaluated resection margin on relapse-free and overall survival. MethodClinicopathological and survival parameters of 264 consecutive patients who underwent surgery for hPDAC were evaluated. ResultsThe rate of R0 resection R0(CRM-) was 48.5%, after the implementation of CRM. Mesopancreatic fat infiltration was evident in 78.4% of all consecutively treated patients. Patients with mesopancreatic fat infiltration were prone to lymphatic metastases (N1 and N2) and had a higher rate of positive resection margin (R1/R0(CRM+)). In multivariate analysis, only R0 resection was shown to be an independent prognostic parameter. Local recurrence was diagnosed in only 21.1% and was significantly lower in patients with R0(CRM-) resected hPDACs (10.9%, p < 0.001). ConclusionMesopancreatic excision is justified, since mesopancreatic fat invasion was evident in the majority of our patients. It is associated with a significantly improved local tumor control as well as longer relapse-free and overall survival.

Precision vascular anatomy for minimally invasive distal pancreatectomy: A systematic review.

Minimally invasive distal pancreatectomy (MIDP) is increasingly performed worldwide; however, the surgical anatomy required to safely perform MIDP has not yet been fully considered. This review evaluated the literature concerning peripancreatic vascular anatomy, which is considered important to conduct safe MIDP. A database search of PubMed and Ichushi (Japanese) was conducted. Qualified studies investigating the anatomical variations of peripancreatic vessels related to MIDP were evaluated using SIGN methodology. Of 701 articles yielded by our search strategy, 76 articles were assessed in this systematic review. The important vascular anatomy required to recognize MIDP included the pancreatic parenchymal coverage on the root and the running course of the splenic artery, branching patterns of the splenic artery, confluence positions of the left gastric vein and the inferior mesenteric vein, forms of pancreatic veins including the centro-inferior pancreatic vein, characteristics of the left renal vein, and collateral routes perfusing the spleen following Warshaw's technique. Very few articles evaluating the relationship between the anatomical variations and surgical outcomes of MIDP were found. The precise knowledge of peripancreatic vessels is important to adequately complete MIDP. More detailed anatomic analyses and descriptions will benefit surgeons and their patients who are facing these operations.