CT virtual pancreatoscopy: a new method for diagnosing intraductal papillary mucinous neoplasm (IPMN) of the pancreas

Open-source algorithm and software for computed tomography-based virtual pancreatoscopy and other applications

Pancreatoscopy plays a significant role in the diagnosis and treatment of pancreatic diseases. However, the risk of pancreatoscopy is remarkably greater than that of other endoscopic procedures, such as gastroscopy and bronchoscopy, owing to its severe invasiveness. In comparison, virtual pancreatoscopy (VP) has shown notable advantages. However, because of the low resolution of current computed tomography (CT) technology and the small diameter of the pancreatic duct, VP has limited clinical use. In this study, an optimal path algorithm and super-resolution technique are investigated for the development of an open-source software platform for VP based on 3D Slicer. The proposed segmentation of the pancreatic duct from the abdominal CT images reached an average Dice coefficient of 0.85 with a standard deviation of 0.04. Owing to the excellent segmentation performance, a fly-through visualization of both the inside and outside of the duct was successfully reconstructed, thereby demonstrating the feasibility of VP. In addition, a quantitative analysis of the wall thickness and topology of the duct provides more insight into pancreatic diseases than a fly-through visualization. The entire VP system developed in this study is available at https://github.com/gaoyi/VirtualEndoscopy.git.

A cascaded fully convolutional network framework for dilated pancreatic duct segmentation

PURPOSE

Pancreatic duct dilation can be considered an early sign of pancreatic ductal adenocarcinoma (PDAC). However, there is little existing research focused on dilated pancreatic duct segmentation as a potential screening tool for people without PDAC. Dilated pancreatic duct segmentation is difficult due to the lack of readily available labeled data and strong voxel imbalance between the pancreatic duct region and other regions. To overcome these challenges, we propose a two-step approach for dilated pancreatic duct segmentation from abdominal computed tomography (CT) volumes using fully convolutional networks (FCNs).

METHODS

Our framework segments the pancreatic duct in a cascaded manner. The pancreatic duct occupies a tiny portion of abdominal CT volumes. Therefore, to concentrate on the pancreas regions, we use a public pancreas dataset to train an FCN to generate an ROI covering the pancreas and use a 3D U-Net-like FCN for coarse pancreas segmentation. To further improve the dilated pancreatic duct segmentation, we deploy a skip connection on each corresponding resolution level and an attention mechanism in the bottleneck layer. Moreover, we introduce a combined loss function based on Dice loss and Focal loss. Random data augmentation is adopted throughout the experiments to improve the generalizability of the model.

RESULTS

We manually created a dilated pancreatic duct dataset with semi-automated annotation tools. Experimental results showed that our proposed framework is practical for dilated pancreatic duct segmentation. The average Dice score and sensitivity were 49.9% and 51.9%, respectively. These results show the potential of our approach as a clinical screening tool.

CONCLUSIONS

We investigate an automated framework for dilated pancreatic duct segmentation. The cascade strategy effectively improved the segmentation performance of the pancreatic duct. Our modifications to the FCNs together with random data augmentation and the proposed combined loss function facilitate automated segmentation.

Branch-type intraductal papillary mucinous neoplasms: an update

BACKGROUND/AIMS

Branch-type intraductal papillary mucinous neoplasms (BT-IPMNs) are a subset of non-inflammatory mucinous lesions of the pancreas. Selected BT-IPMNs can be managed conservatively by surveillance because of their lower malignant potential. This review aims to update the reader on advances in our knowledge of BT-IPMNs since the consensus guidelines published in 2006.

METHODS

A Pubmed search for BT-IPMNs was undertaken and relevant papers were reviewed.

RESULTS

Due to the relative scarcity of this condition, still little is known about the natural history, the best method of surveillance or the surgical and non-surgical options.

CONCLUSION

A national database of BT-IPMNs would enable a large enough cohort of patients to be followed up and valid conclusions drawn regarding the best method of treatment or surveillance. and IAP.

Primary pancreatic cystic neoplasms revisited. Part III. Intraductal papillary mucinous neoplasms

Intraductal papillary mucinous neoplasms (IPMNs) represent about 25% of all primary pancreatic cystic neoplasms and are increasingly recognized during the last two decades. They are characterized by intraductal proliferation of neoplastic mucinous cells forming papillary projections into the pancreatic ductal system, which is typically dilated and contains globules of mucus. IPMNs may be multifocal and have malignant potential. Modern imaging is essential in establishing preoperative diagnosis and in differentiating different subtypes of IPMNs (i.e., main-duct vs. branch-type disease). Endoscopic retrograde or magnetic resonance cholangiopancreatography accurately delineate the morphologic changes of the pancreatic ductal system. Endoscopic ultrasonography (usually used in conjunction with image-guided FNA and analysis of the aspirated material) is commonly used for differential diagnosis of IPMNs from other pancreatic cystic lesions. Surgical resection (usually anatomic pancreatectomy, depending on the location of the disease) is the treatment of choice. Total pancreatectomy may occasionally be required in selected patients, but is associated with formidable long-term morbidity. A conservative approach has recently been proposed for carefully selected patients with branch-duct IPMNs. Recurrences following surgical resection can be observed, especially in patients with multifocal disease or in the presence of underlying malignancy.

Development of a virtual reality guided diagnostic tool based on magnetic resonance imaging

Computed tomography (CT) and virtual reality (VR) made it possible to create internal views of the human body without actual penetration. During the last two decades, several endoscopic diagnosis procedures have received virtual counter candidates. This paper presents an own concept of a virtual reality guided diagnostic tool, based on magnetic resonance images representing parallel cross-sections of the investigated organ. A series of image processing methods are proposed for image quality enhancement, accurate segmentation in two dimensions, and three-dimensional reconstruction of detected surfaces. These techniques provide improved accuracy in image segmentation, and thus they represent excellent support for three dimensional imaging. The implemented software system allows interactive navigation within the investigated volume, and provides several facilities to quantify important physical properties including distances, areas, and volumes.

Intraductal papillary mucinous neoplasms of the pancreas: diagnosis and management

Intraductal papillary mucinous neoplasms (IPMNs), characterized by intraductal papillary growth and thick mucin secretion, have increasingly been recognized. Despite modern preoperative evaluation, major difficulties still remain in distinguishing malignant invasive types from benign IPMNs. Following a PubMed database search, all relevant abstracts and articles on IPMN published in English and Chinese were reviewed. Main-duct and the mixed type IPMNs carry a higher risk of malignancy as compared with branch-duct type IPMNs. Treatment of branch-duct type IPMNs remains controversial. Once operation is indicated, intraoperative frozen section of margins plays an important role in the decision concerning the extent and type of surgery. Pancreatectomy, partly preserving both endocrine and exocrine pancreatic function, is advocated for most patients with IPMN, though total pancreatectomy may be necessary in some. Both for patients subjected to surgery and those only observed, IPMN patients need regular close follow-up to identify recurrence or progressive disease.

New anatomical data on the drainage patterns of the uncinate process of the pancreas

PURPOSE

Recently, progress has been made in the surgical management of benign pancreatic tumors sparing as much of the pancreatic parenchyma and pancreatic function as possible. However, the main complication of partial pancreatectomy is the disruption of pancreatic ducts ensuing leak of pancreatic secretion leading to the formation of pancreatic fistulae. In this study, we attempt to precisely define the anatomy of the branch duct draining the uncinate process which is of interest to the surgeons.

METHODS

Seventeen formalin-fixed pancreases were taken and ducts were injected with a colored gelatin solution. Within the uncinate process of the pancreases, the branch duct was localized, measured and its anatomical drainage defined. Statistics were performed using Spearman's correlation test.

RESULTS

The uncinate process was drained exclusively by the main pancreatic duct in ten cases, by the accessory pancreatic duct in three cases, and by both the ducts in four cases. All of the branches drained into the main pancreatic duct downstream to the junction between the main and the accessory pancreatic duct, except for one.

CONCLUSIONS

We have precised the possibility of double drainage of the uncinate process, but this could not be correlated with simple anatomical or radiological landmarks such as the length of the main pancreatic duct or the patency of the minor duodenal papilla.

Intraductal papillary mucinous neoplasms

Intraductal papillary mucinous neoplasm (IPMN) is characterized by enhanced mucus secretion. It is a benign or low-grade neoplasm associated with a dilated main pancreatic duct, patulous ampullary orifice, and abundant mucus secretion. Foci of aggressive cancer may arise and become invasive. Surgery is the only treatment that can cure IPMN, but the extent of pancreatic resection and the intraoperative margins remain areas of controversy. The risks of total pancreatectomy must be weighed against the risk for developing cancer in the residual pancreas. Risks must be factored against the natural course of the disease and the likelihood of malignancy developing over the life expectancy.

New advances in pancreatic imaging

PURPOSE OF REVIEW

This review serves to highlight new technology and novel applications of existing techniques and their role in the management of pancreatic diseases, including acute and chronic pancreatitis, pancreatic cancer, and pancreatic cystic neoplasms.

RECENT FINDINGS

Contrast-enhanced ultrasound has shown promise in evaluating the severity of acute pancreatitis, staging pancreatic cancer, and predicting malignancy in cystic neoplasms. Optical coherence tomography within the pancreatic duct appears to be able to differentiate malignant and normal pancreatic ducts. Spectroscopy may prove useful in differentiating focal chronic pancreatitis from malignancy. Multidetector-row computed tomography may provide more accurate information regarding cancer respectability and differentiation between ductal type of intraductal papillary mucinous tumors.

SUMMARY

These new developments will help with the diagnosis and staging of pancreatic diseases.