Hidden in plain sight: commonly missed early signs of pancreatic cancer on CT

Pancreatic ductal adenocarcinoma (PDAC) has poor prognosis mostly due to the advanced stage at which disease is diagnosed. Early detection of disease at a resectable stage is, therefore, critical for improving outcomes of patients. Prior studies have demonstrated that pancreatic abnormalities may be detected on CT in up to 38% of CT studies 5 years before clinical diagnosis of PDAC. In this review, we highlight commonly missed signs of early PDAC on CT. Broadly, these commonly missed signs consist of small isoattenuating PDAC without contour deformity, isolated pancreatic duct dilatation and cutoff, focal pancreatic enhancement and focal parenchymal atrophy, pancreatitis with underlying PDAC, and vascular encasement. Through providing commentary on demonstrative examples of these signs, we demonstrate how to reduce the risk of missing or misinterpreting radiological features of early PDAC.

Pancreatectomy with En Bloc Superior Mesenteric Vein and All Its Tributaries Resection without PV/SMV Reconstruction for "Low" Locally Advanced Pancreatic Head Cancer

The "vein definition" for locally advanced pancreatic ductal adenocarcinoma (LA PDAC) assumes portal-to-superior mesenteric vein (PV/SMV) unreconstructability due to tumor involvement or occlusion. Radical pancreatectomies with SMV resection without PV/SMV reconstruction are scarcely discussed in the literature. Retrospective analysis of 19 radical pancreatectomies for "low" LA PDAC with SMV and all its tributaries resection without PV/SMV reconstruction has shown zero mortality; overall morbidity-56%; Dindo-Clavien-3-10.5%; R0-rate-82%; mean operative procedure time-355 ± 154 min; mean blood loss-330 ± 170 mL; delayed gastric emptying-25%; and clinically relevant postoperative pancreatic fistula-8%. In three cases, surgery was associated with superior mesenteric (n2) and common hepatic artery (n1) resection. Surgery was completed without vein reconstruction (n13) and with inferior mesenteric-to-splenic anastomosis (n6). There were no cases of liver, gastric, or intestinal ischemia. A specific complication of the SMV resection without reconstruction was 2-3 days-long intestinal edema (48%). Median overall survival was 25 months, and median progression-free survival was 18 months. All the relapses, except two, were distant. The possibility of successful SMV resection without PV/SMV reconstruction can be predicted before surgery by CT-based reconstructions. The mandatory anatomical conditions for the procedure were as follows: (1) preserved SMV-SV confluence; (2) occluded SMV for any reason (tumor or thrombus); (3) well-developed inferior mesenteric vein collaterals with dilated intestinal veins; (4) no right-sided vein collaterals; and (5) no varices in the upper abdomen. Conclusion: "Low" LA PDACs involving SMV with all its tributaries can be radically and safely resected in highly and specifically selected cases without PV/SMV reconstruction with an acceptable survival rate.

Imaging of pancreatic ductal adenocarcinoma - An update for all stages of patient management

Background

Pancreatic ductal adenocarcinoma (PDAC) is a common and lethal cancer. From diagnosis to disease staging, response to neoadjuvant therapy assessment and patient surveillance after resection, imaging plays a central role, guiding the multidisciplinary team in decision-planning.

Review aims and findings

This review discusses the most up-to-date imaging recommendations, typical and atypical findings, and issues related to each step of patient management. Example cases for each relevant condition are presented, and a structured report for disease staging is suggested.

Conclusion

Despite current issues in PDAC imaging at different stages of patient management, the radiologist is essential in the multidisciplinary team, as the conveyor of relevant imaging findings crucial for patient care.

Development and validation of a model for predicting the expression of Ki-67 in pancreatic ductal adenocarcinoma with radiological features and dual-energy computed tomography quantitative parameters

OBJECTIVE

To construct and validate a model based on the dual-energy computed tomography (DECT) quantitative parameters and radiological features to predict Ki-67 expression levels in pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

Data from 143 PDAC patients were analysed. The variables of clinic, radiology and DECT were evaluated. In the arterial phase and portal venous phase (PVP), the normalized iodine concentration (NIC), normalized effective atomic number and slope of the spectral attenuation curves were measured. The extracellular volume fraction (ECVf) was measured in the equilibrium phase. Univariate analysis was used to screen independent risk factors to predict Ki-67 expression. The Radiology, DECT and DECT-Radiology models were constructed, and their diagnostic effectiveness and clinical applicability were obtained through area under the curve (AUC) and decision curve analysis, respectively. The nomogram was established based on the optimal model, and its goodness-of-fit was assessed by a calibration curve.

RESULTS

Computed tomography reported regional lymph node status, NIC of PVP, and ECVf were independent predictors for Ki-67 expression prediction. The AUCs of the Radiology, DECT, and DECT-Radiology models were 0.705, 0.884, and 0.905, respectively, in the training cohort, and 0.669, 0.835, and 0.865, respectively, in the validation cohort. The DECT-Radiology nomogram was established based on the DECT-Radiology model, which showed the highest net benefit and satisfactory consistency.

CONCLUSIONS

The DECT-Radiology model shows favourable predictive efficacy for Ki-67 expression, which may be of value for clinical decision-making in PDAC patients.

CRITICAL RELEVANCE STATEMENT

The DECT-Radiology model could contribute to the preoperative and non-invasive assessment of Ki-67 expression of PDAC, which may help clinicians to screen out PDAC patients with high Ki-67 expression.

KEY POINTS

• Dual-energy computed tomography (DECT) can predict Ki-67 in pancreatic ductal adenocarcinoma (PDAC). • The DECT-Radiology model facilitates preoperative and non-invasive assessment of PDAC Ki-67 expression. • The nomogram may help screen out PDAC patients with high Ki-67 expression.

Imaging after Pancreatic Surgery: Expected Findings and Postoperative Complications

Pancreatic surgery is considered one of the most technically challenging surgical procedures, despite the evolution of modern techniques. Neoplasms remain the most common indication for pancreatic surgery, although inflammatory conditions may also prompt surgical evaluation. The choice of surgical procedure depends on the type and location of the pathologic finding because different parts of the pancreas have separate vascular supplies that may be shared by adjacent organs. The surgical approach could be conventional or minimally invasive (laparoscopic, endoscopic, or robotic assisted). Because of the anatomic complexity of the pancreatic bed, perioperative complications may be frequently encountered and commonly involve the pancreatic-biliary, vascular, lymphatic, or bowel systems, irrespective of the surgical technique used. Imaging plays an important role in the assessment of suspected postoperative complications, with CT considered the primary imaging modality, while MRI, digital subtraction angiography, and molecular imaging are considered ancillary diagnostic tools. Accurate diagnosis of postoperative complications requires a solid understanding of pancreatic anatomy, surgical indications, normal postoperative appearance, and expected postsurgical changes. The practicing radiologist should be familiar with the most common perioperative complications, such as anastomotic leak, abscess, and hemorrhage, and be able to differentiate these entities from normal anticipated postoperative changes such as seroma, edema and fat stranding at the surgical site, and perivascular soft-tissue thickening. In addition to evaluation of the primary operative fossa, imaging plays a fundamental role in assessment of the adjacent organ systems secondarily affected after pancreatic surgery, such as vascular, biliary, and enteric complications. Published under a CC BY 4.0 license. Test Your Knowledge questions are available in the supplemental material. See the invited commentary by Winslow in this issue.

Preoperative prediction of disease-free survival in pancreatic ductal adenocarcinoma patients after R0 resection using contrast-enhanced CT and CA19-9

OBJECTIVES

To investigate the efficiency of a combination of preoperative contrast-enhanced computed tomography (CECT) and carbohydrate antigen 19-9 (CA19-9) in predicting disease-free survival (DFS) after R0 resection of pancreatic ductal adenocarcinoma (PDAC).

METHODS

A total of 138 PDAC patients who underwent curative R0 resection were retrospectively enrolled and allocated chronologically to training (n = 91, January 2014-July 2019) and validation cohorts (n = 47, August 2019-December 2020). Using univariable and multivariable Cox regression analyses, we constructed a preoperative clinicoradiographic model based on the combination of CECT features and serum CA19-9 concentrations, and validated it in the validation cohort. The prognostic performance was evaluated and compared with that of postoperative clinicopathological and tumor-node-metastasis (TNM) models. Kaplan-Meier analysis was conducted to verify the preoperative prognostic stratification performance of the proposed model.

RESULTS

The preoperative clinicoradiographic model included five independent prognostic factors (tumor diameter on CECT > 4 cm, extrapancreatic organ infiltration, CECT-reported lymph node metastasis, peripheral enhancement, and preoperative CA19-9 levels > 180 U/mL). It better predicted DFS than did the postoperative clinicopathological (C-index, 0.802 vs. 0.787; p < 0.05) and TNM (C-index, 0.802 vs. 0.711; p < 0.001) models in the validation cohort. Low-risk patients had significantly better DFS than patients at the high-risk, defined by the model preoperatively (p < 0.001, training cohort; p < 0.01, validation cohort).

CONCLUSIONS

The clinicoradiographic model, integrating preoperative CECT features and serum CA19-9 levels, helped preoperatively predict postsurgical DFS for PDAC and could facilitate clinical decision-making.

CLINICAL RELEVANCE STATEMENT

We constructed a simple model integrating clinical and radiological features for the prediction of disease-free survival after curative R0 resection in patients with pancreatic ductal adenocarcinoma; this novel model may facilitate preoperative identification of patients at high risk of recurrence and metastasis that may benefit from neoadjuvant treatments.

KEY POINTS

• Existing clinicopathological predictors for prognosis in pancreatic ductal adenocarcinoma (PDAC) patients who underwent R0 resection can only be ascertained postoperatively and do not allow preoperative prediction. • We constructed a clinicoradiographic model, using preoperative contrast-enhanced computed tomography (CECT) features and preoperative carbohydrate antigen 19-9 (CA19-9) levels, and presented it as a nomogram. • The presented model can predict disease-free survival (DFS) in patients with PDAC better than can postoperative clinicopathological or tumor-node-metastasis (TNM) models.

Preoperative assessment of peripheral vascular invasion of pancreatic ductal adenocarcinoma based on high-resolution MRI

OBJECTIVES

Preoperative imaging of vascular invasion is important for surgical resection of pancreatic ductal adenocarcinoma (PDAC). However, whether MRI and CT share the same evaluation criteria remains unclear. This study aimed to compare the diagnostic accuracy of high-resolution MRI (HR-MRI), conventional MRI (non-HR-MRI) and CT for PDAC vascular invasion.

METHODS

Pathologically proven PDAC with preoperative HR-MRI (79 cases, 58 with CT) and non-HR-MRI (77 cases, 59 with CT) were retrospectively collected. Vascular invasion was confirmed surgically or pathologically. The degree of tumour-vascular contact, vessel narrowing and contour irregularity were reviewed respectively. Diagnostic criteria 1 (C1) was the presence of all three characteristics, and criteria 2 (C2) was the presence of any one of them. The diagnostic efficacies of different examination methods and criteria were evaluated and compared.

RESULTS

HR-MRI showed satisfactory performance in assessing vascular invasion (AUC: 0.87-0.92), especially better sensitivity (0.79-0.86 vs. 0.40-0.79) than that with non-HR-MRI and CT. HR-MRI was superior to non-HR-MRI. C2 was superior to C1 on CT evaluation (0.85 vs. 0.79, P = 0.03). C1 was superior to C2 in the venous assessment using HR-MRI (0.90 vs. 0.87, P = 0.04) and in the arterial assessment using non-HR-MRI (0.69 vs. 0.68, P = 0.04). The combination of C1-assessed HR-MRI and C2-assessed CT was significantly better than that of CT alone (0.96 vs. 0.86, P = 0.04).

CONCLUSIONS

HR-MRI more accurately assessed PDAC vascular invasion than conventional MRI and may contribute to operative decision-making. C1 was more applicable to MRI scans, and C2 to CT scans. The combination of C1-assessed HR-MRI and C2-assessed CT outperformed CT alone and showed the best efficacy in preoperative examination of PDAC.

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.

Synergistic neuroprotection by phytocompounds of Bacopa monnieri in scopolamine-induced Alzheimer's disease mice model

BACKGROUND

Millions of people around the globe are affected by Alzheimer's disease (AD). This crippling condition has no treatment despite intensive studies. Some phytocompounds have been shown to protect against Alzheimer's in recent studies.

METHODS

Thus, this work aimed to examine Bacopa monnieri phytocompounds' synergistic effects on neurodegeneration, antioxidant activity, and cognition in the scopolamine-induced AD mice model. The toxicity study of two phytocompounds: quercetin and bacopaside X revealed an LD50 of more than 2000 mg/kg since no deaths occurred.

RESULTS

The neuroprotection experiment consists of 6 groups i.e., control (saline), scopolamine (1 mg/kg), donepezil (5 mg/kg), Q (25 mg/kg), BX (20 mg/kg), and Q + BX (25 mg/kg + 20 mg/kg). Visual behavioral assessment using the Morris water maze showed that animals in the diseased model group (scopolamine) moved more slowly toward the platform and exhibited greater thigmotaxis behavior than the treatment and control groups. Likewise, the concentration of biochemical NO, GSH, and MDA improved in treatment groups concerning the diseased group. mRNA levels of different marker genes including ChAT, IL-1α, IL-1 β, TNF α, tau, and β secretase (BACE1) improved in treatment groups with respect to the disease group.

CONCLUSION

Both bacopaside X and quercetin synergistically have shown promising results in neuroprotection. Therefore, it is suggested that Q and BX may work synergistically due to their antioxidant and neuroprotective property.

Exploratory analysis of mesenteric-portal axis CT radiomic features for survival prediction of patients with pancreatic ductal adenocarcinoma

OBJECTIVE

To develop and evaluate task-based radiomic features extracted from the mesenteric-portal axis for prediction of survival and response to neoadjuvant therapy in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Consecutive patients with PDAC who underwent surgery after neoadjuvant therapy from two academic hospitals between December 2012 and June 2018 were retrospectively included. Two radiologists performed a volumetric segmentation of PDAC and mesenteric-portal axis (MPA) using a segmentation software on CT scans before (CTtp0) and after (CTtp1) neoadjuvant therapy. Segmentation masks were resampled into uniform 0.625-mm voxels to develop task-based morphologic features (n = 57). These features aimed to assess MPA shape, MPA narrowing, changes in shape and diameter between CTtp0 and CTtp1, and length of MPA segment affected by the tumor. A Kaplan-Meier curve was generated to estimate the survival function. To identify reliable radiomic features associated with survival, a Cox proportional hazards model was used. Features with an ICC  ≥ 0.80 were used as candidate variables, with clinical features included a priori.

RESULTS

In total, 107 patients (60 men) were included. The median survival time was 895 days (95% CI: 717, 1061). Three task-based shape radiomic features (Eccentricity mean tp0, Area minimum value tp1, and Ratio 2 minor tp1) were selected. The model showed an integrated AUC of 0.72 for prediction of survival. The hazard ratio for the Area minimum value tp1 feature was 1.78 (p = 0.02) and 0.48 for the Ratio 2 minor tp1 feature (p = 0.002).

CONCLUSION

Preliminary results suggest that task-based shape radiomic features can predict survival in PDAC patients.

KEY POINTS

• In a retrospective study of 107 patients who underwent neoadjuvant therapy followed by surgery for PDAC, task-based shape radiomic features were extracted and analyzed from the mesenteric-portal axis. • A Cox proportional hazards model that included three selected radiomic features plus clinical information showed an integrated AUC of 0.72 for prediction of survival, and a better fit compared to the model with only clinical information.

Neoadjuvant chemotherapy and radiotherapy outcomes in borderline-resectable and locally-advanced pancreatic cancer patients

BACKGROUND

There is no agreed upon standard of care for borderline-resectable pancreatic cancer (BRPC) or locally-advanced pancreatic cancer (LAPC) patients regarding the benefit of chemotherapy or radiation alone or in combination.

PATIENTS AND METHODS

We completed a retrospective cohort analysis of BRPC and LAPC patients at a cancer center with expertise in multi-disciplinary pancreatic ductal adenocarcinoma (PDAC) treatment over a 5-year period from 03/01/2014 to 03/01/2019 (cut-off date). The total evaluable newly diagnosed, treatment naïve, BRPC, and LAPC patients with adequate organ function and ability to obtain treatment after multidisciplinary review was 52 patients. After analysis, patients were evaluated for rates of resection, extent of resection (R0 or R1), median progression-free survival (mPFS), and median overall survival (mOS).

RESULTS

Patients were treated with chemotherapy alone (gemcitabine and nab-paclitaxel = 77% (20/26); FOLFIRINOX = 19% (5/26); single agent gemcitabine 3.8% (1/26)), or chemotherapy followed by chemoradiation (gemcitabine +5 Gy × 5 weeks), or chemoradiation alone prior to re-staging and potential resection. Of the 29% (15/52) of patients who went on to surgical resection, 73% (11/15) achieved R0 resection. An R0 resection was achieved in 35% (9/26) of patients treated with chemotherapy alone, 7.6% (1/13) in a patient treated with chemotherapy followed by radiation, and 7.6% (1/13) with concurrent chemoradiotherapy alone. Chemotherapy alone achieved a mPFS of 16.4 months (p  < 0.0025) and mOS of 26.2 months (p  < 0.0001), chemotherapy followed by chemoradiation was 13.0 months and 14.9 months respectively, while concurrent chemoradiotherapy was 6.9 months and 7.3 months.

CONCLUSIONS AND RELEVANCE

BRPC and LAPC patients capable of surgery after only receiving neoadjuvant treatment with chemotherapy had higher rates of R0 resection with prolonged median PFS and OS compared with any patient needing combination chemotherapy with radiotherapy.

Extracellular volume fraction determined by dual-layer spectral detector CT: Possible role in predicting the efficacy of preoperative neoadjuvant chemotherapy in pancreatic ductal adenocarcinoma

PURPOSE

To clarify the relationship between extracellular volume (ECV) measured by dual-energy CT (DECT) and efficacy of preoperative neoadjuvant chemotherapy (NAC) in patients with pancreatic ductal adenocarcinoma (PDAC), as compared with single-energy CT (SECT).

METHODS

We enrolled 67 patients with PDAC who underwent dynamic contrast-enhanced CT with a dual-energy CT system prior to NAC. Attenuation values were measured on unenhanced and the equilibrium-phase 120-kVp equivalent CT images for PDAC and the aorta. ΔHU-tumor, ΔHU-tumor/ΔHU-aorta, and SECT-ECV were calculated. Iodine densities of the tumor and aorta were measured in the equilibrium phase, and DECT-ECV of the tumor was calculated. Response to NAC was evaluated and the correlation between imaging parameters and response to NAC was statistically assessed.

RESULTS

Tumor DECT-ECVs were significantly lower in the response group (n = 7) than in the non-response group (n = 60), with most significant difference (p = 0.0104). DECT-ECV showed highest diagnostic value with an Az value of 0.798. When using the optimal cut off value of DECT-ECV (<26.0 %), sensitivity, specificity, accuracy, positive predictive value, and negative value for predicting response group were 71.4 %, 85.0 %, 83.6 %, 35.7 % and 96.2 %, respectively.

CONCLUSION

PDAC with lower DECT-ECV can potentially show better response to NAC. DECT-ECV might be a useful biomarker for predicting response to NAC in patients with PDAC.

Cinematic Rendering: Novel Tool for Improving Pancreatic Cancer Surgical Planning

Pancreatic ductal adenocarcinoma is the third-leading cause of all cancer-related deaths in the US. While 20% of patients have resectable disease at diagnosis, improved control of systemic disease using effective chemotherapeutic regimens allows for aggressive operations involving complex vascular resection and reconstruction. A pancreas protocol computed tomography (PPCT) is the gold standard imaging modality in determining local resectability (degree of tumor-vessel involvement), however, it is limited by the inter-operator variability. While post-processing-3D-rendering helps, it does not allow for real-time dynamic assessment of resectability. A recent development in post-process-rendering called cinematic rendering (CR) overcomes this by utilizing advanced light modeling to generate photorealistic 3D images with enhanced details. Cinematic rendering allows for nuanced visualization of areas of interest. Our preliminary experience, as one of the first centers to incorporate the routine use of CR, has proven very useful in surgical planning. For local determination of resectability, vascular mapping allows for accurate assessment of major arteries and the portovenous system. For the portovenous anatomy it assists in determining the optimal surgical approach (extent of resection, appropriate technique for reconstruction, and need for mesocaval shunting). For arterial anatomy, vessel encasement either represents dissectible involvement via periadventitial dissection or true vessel invasion that is unresectable. CR could potentially provide superior ability than traditional PPCT to discern between the two. Additionally, CR allows for better 3D visualization of arterial anatomic variants which, if not appreciated preoperatively, increases risk of intraoperative ischemia and postoperative complications. Lastly, CR could help avoid unnecessary surgery by enhanced identification of occult metastatic disease that is metastatic disease that is otherwise not appreciated on a standard PPCT.

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

Objectives

To 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 methods

This 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.

Results

All 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).

Conclusions

Low-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.

Radiomics and Its Applications and Progress in Pancreatitis: A Current State of the Art Review

Radiomics involves high-throughput extraction and analysis of quantitative information from medical images. Since it was proposed in 2012, there are some publications on the application of radiomics for (1) predicting recurrent acute pancreatitis (RAP), clinical severity of acute pancreatitis (AP), and extrapancreatic necrosis in AP; (2) differentiating mass-forming chronic pancreatitis (MFCP) from pancreatic ductal adenocarcinoma (PDAC), focal autoimmune pancreatitis (AIP) from PDAC, and functional abdominal pain (functional gastrointestinal diseases) from RAP and chronic pancreatitis (CP); and (3) identifying CP and normal pancreas, and CP risk factors and complications. In this review, we aim to systematically summarize the applications and progress of radiomics in pancreatitis and it associated situations, so as to provide reference for related research.

Preoperative predictors for early and very early disease recurrence in patients undergoing resection of pancreatic ductal adenocarcinoma

BACKGROUND

This study aimed to identify predictors for early and very early disease recurrence in patients undergoing resection of pancreatic ductal adenocarcinoma (PDAC) resection with and without neoadjuvant therapy.

METHODS

Included were patients who underwent PDAC resection (2014-2016). Multivariable multinomial regression was performed to identify preoperative predictors for manifestation of recurrence within 3, 6 and 12 months after PDAC resection.

RESULTS

836 patients with a median follow-up of 37 (interquartile range [IQR] 30-48) months and overall survival of 18 (IQR 10-32) months were analyzed. 670 patients (80%) developed recurrence: 82 patients (10%) <3 months, 96 patients (11%) within 3-6 months and 226 patients (27%) within 6-12 months. LogCA 19-9 (OR 1.25 [95% CI 1.10-1.41]; P < 0.001) and neoadjuvant treatment (OR 0.09 [95% CI 0.01-0.68]; P = 0.02) were associated with recurrence <3 months. LogCA 19-9 (OR 1.23 [95% CI 1.10-1.38]; P < 0.001) and 0-90° venous involvement on CT imaging (OR 2.93 [95% CI 1.60-5.37]; P < 0.001) were associated with recurrence within 3-6 months. A Charlson Age Comorbidity Index ≥4 (OR 1.53 [95% CI 1.09-2.16]; P = 0.02) and logCA 19-9 (OR 1.24 [95% CI 1.14-1.35]; P < 0.001) were related to recurrence within 6-12 months.

CONCLUSION

This study demonstrates preoperative predictors that are associated with the manifestation of early and very early recurrence after PDAC resection. Knowledge of these predictors can be used to guide individualized surveillance and treatment strategies.

Imaging Assessment of Pancreatic Cancer Resectability After Neoadjuvant Therapy: AJR Expert Panel Narrative Review

Despite important innovations in the treatment of pancreatic ductal adenocarcinoma (PDAC), PDAC remains a disease with poor prognosis and high mortality. A key area for potential improvement in the management of PDAC, aside from earlier detection in patients with treatable disease, is the improved ability of imaging techniques to differentiate treatment response after neoadjuvant therapy (NAT) from worsening disease. It is well established that current imaging techniques cannot reliably make this distinction. This narrative review provides an update on the imaging assessment of pancreatic cancer resectability after NAT. Current definitions of borderline resectable PDAC, as well as implications for determining likely patient benefit from NAT, are described. Challenges associated with PDAC pathologic evaluation and surgical decision making that are of relevance to radiologists are discussed. Also explored are the specific limitations of imaging in differentiating the response after NAT from stable or worsening disease, including issues relating to protocol optimization, tumor size assessment, vascular assessment, and liver metastasis detection. The roles of MRI as well as PET and/or hybrid imaging are considered. Finally, a short PDAC reporting template is provided for use after NAT. The highlighted methods seek to improve radiologists' assessment of PDAC treatment response after NAT.

Prediction of vascular invasion using a 7-point scale computed tomography grading system in adrenal tumors in dogs

BACKGROUND

Previous studies evaluating the accuracy of computed tomography (CT) in detecting caudal vena cava (CVC) invasion by adrenal tumors (AT) used a binary system and did not evaluate for other vessels.

OBJECTIVE

Test a 7-point scale CT grading system for accuracy in predicting vascular invasion and for repeatability among radiologists. Build a decision tree based on CT criteria to predict tumor type.

METHODS

Retrospective observational cross-sectional case study. Abdominal CT studies were analyzed by 3 radiologists using a 7-point CT grading scale for vascular invasion and by 1 radiologist for CT features of AT.

ANIMALS

Dogs with AT that underwent adrenalectomy and had pre- and postcontrast CT.

RESULTS

Ninety-one dogs; 45 adrenocortical carcinomas (50%), 36 pheochromocytomas (40%), 9 adrenocortical adenomas (10%) and 1 unknown tumor. Carcinoma and pheochromocytoma differed in pre- and postcontrast attenuation, contralateral adrenal size, tumor thrombus short- and long-axis, and tumor and thrombus mineralization. A decision tree was built based on these differences. Adenoma and malignant tumors differed in contour irregularity. Probability of vascular invasion was dependent on CT grading scale, and a large equivocal zone existed between 3 and 6 scores, lowering CT accuracy to detect vascular invasion. Radiologists' agreement for detecting abnormalities (evaluated by chance-corrected weighted kappa statistics) was excellent for CVC and good to moderate for other vessels. The quality of postcontrast CT study had a negative impact on radiologists' performance and agreement.

CONCLUSIONS AND CLINICAL IMPORTANCE

Features of CT may help radiologists predict AT type and provide probabilistic information on vascular invasion.

Dual-energy CT with virtual monoenergetic images to improve the visualization of pancreatic supplying arteries: the normal anatomy and variations

Background

Pancreatic ductal adenocarcinoma (PDAC) remains a malignancy with poor prognosis, appropriate surgical resection and neoadjuvant therapy depend on the accurate identification of pancreatic supplying arteries. We aim to evaluate the ability of monoenergetic images (MEI [+]) of dual-energy CT (DECT) to improve the visualization of pancreatic supplying arteries compared to conventional polyenergetic images (PEI) and investigate the implications of vascular variation in pancreatic surgery and transarterial interventions.

Results

One hundred patients without pancreatic diseases underwent DECT examinations were retrospectively enrolled in this study. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) at 40-keV MEI (+) were significantly higher than those of PEI (p < 0.05). All subjective MEI (+) scores were significantly higher than those of PEI (p < 0.05). The visualization rates were significantly higher for posterior superior pancreaticoduodenal artery (PSPDA), anterior and posterior inferior pancreaticoduodenal artery (AIPDA, PIPDA), anterior and posterior pancreaticoduodenal arcade (APAC, PPAC), transverse and caudal pancreatic artery (TPA, PCA) at 40-keV MEI (+) than those of PEI (p < 0.05). However, there were no significant differences for visualizing anterior superior pancreaticoduodenal artery (ASPDA), inferior pancreaticoduodenal artery (IPDA), dorsal and magnificent pancreatic artery (DPA, MPA) between 40-keV MEI (+) and PEI (p > 0.05). Four types of variations were observed in the origin of DPA and three to five types in the origin of PSPDA, AIPDA and PIPDA.

Conclusions

40-keV MEI (+) of DECT improves the visualization and objective and subjective image quality of pancreatic supplying arteries compared to PEI. Pancreatic supplying arteries have great variations, which has important implications for preoperative planning of technically challenging surgeries and transarterial interventions.

Structured CT reporting of pancreatic ductal adenocarcinoma: impact on completeness of information and interdisciplinary communication for surgical planning

PURPOSE

With the rise in popularity of structured reports in radiology, we sought to evaluate whether free-text CT reports on pancreatic ductal adenocarcinoma (PDAC) staging at our institute met published guidelines and assess feedback of pancreatic surgeons comparing free-text and structured report styles with the same information content.

METHODS

We retrospectively evaluated 298 free-text preoperative CT reports from 2015 to 2017 for the inclusion of key tumor descriptors. Two surgeons independently evaluated 50 free-text reports followed by evaluation of the same reports in a structured format using a 7-question survey to assess the usefulness and ease of information extraction. Fisher's exact test and Chi-square test for independence were utilized for categorical responses and an independent samples t test for comparing mean ratings of report quality as rated on a 5-point Likert scale.

RESULTS

The most commonly included descriptors in free-text reports were tumor location (99%), liver lesions (97%), and suspicious lymph nodes (97%). The most commonly excluded descriptors were variant arterial anatomy and peritoneal/omental nodularity, which were present in only 23% and 42% of the reports, respectively. For vascular involvement, a mention of the presence or absence of perivascular disease with the main portal vein was most commonly included (87%). Both surgeons' rating of overall report quality was significantly higher for structured reports (p < 0.001).

CONCLUSION

Our results indicate that free-text reports may not include key descriptors for staging PDAC. Surgeons rated structured reports that presented the same information as free-text reports but in a template format superior for guiding clinical management, convenience of use, and overall report quality.

CT Radiomic Features of Superior Mesenteric Artery Involvement in Pancreatic Ductal Adenocarcinoma: A Pilot Study

Background Current imaging methods for prediction of complete margin resection (R0) in patients with pancreatic ductal adenocarcinoma (PDAC) are not reliable. Purpose To investigate whether tumor-related and perivascular CT radiomic features improve preoperative assessment of arterial involvement in patients with surgically proven PDAC. Materials and Methods This retrospective study included consecutive patients with PDAC who underwent surgery after preoperative CT between 2012 and 2019. A three-dimensional segmentation of PDAC and perivascular tissue surrounding the superior mesenteric artery (SMA) was performed on preoperative CT images with radiomic features extracted to characterize morphology, intensity, texture, and task-based spatial information. The reference standard was the pathologic SMA margin status of the surgical sample: SMA involved (tumor cells ≤1 mm from margin) versus SMA not involved (tumor cells >1 mm from margin). The preoperative assessment of SMA involvement by a fellowship-trained radiologist in multidisciplinary consensus was the comparison. High reproducibility (intraclass correlation coefficient, 0.7) and the Kolmogorov-Smirnov test were used to select features included in the logistic regression model. Results A total of 194 patients (median age, 66 years; interquartile range, 60-71 years; age range, 36-85 years; 99 men) were evaluated. Aside from surgery, 148 patients underwent neoadjuvant therapy. A total of 141 patients' samples did not involve SMA, whereas 53 involved SMA. A total of 1695 CT radiomic features were extracted. The model with five features (maximum hugging angle, maximum diameter, logarithm robust mean absolute deviation, minimum distance, square gray level co-occurrence matrix correlation) showed a better performance compared with the radiologist assessment (model vs radiologist area under the curve, 0.71 [95% CI: 0.62, 0.79] vs 0.54 [95% CI: 0.50, 0.59]; P < .001). The model showed a sensitivity of 62% (33 of 53 patients) (95% CI: 51, 77) and a specificity of 77% (108 of 141 patients) (95% CI: 60, 84). Conclusion A model based on tumor-related and perivascular CT radiomic features improved the detection of superior mesenteric artery involvement in patients with pancreatic ductal adenocarcinoma. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Do and Kambadakone in this issue.

Towards an updated view on the clinical management of pancreatic adenocarcinoma: Current and future perspectives

Pancreatic cancer has a dire prognosis and will represent the second leading cause of cancer death in the next 10 years. The multifactorial approach represents one of the main issues in controlling the extension of this neoplasm. In recent years, the characteristics of the tumor microenvironment, metastasis mechanisms and the relationship between immune system and neoplastic cells have been described, which has made it possible to understand the pathophysiology of pancreatic adenocarcinoma. Currently, there is a failure to provide an effective preventive method or early detection, so patients present with an advanced stage at the time of diagnosis. Despite numerous efforts, little progress has been made in clinical outcome and in improving survival in long term. Therefore, in the recent years, diverse diagnostic tests, treatments and possible approaches have been developed in the fields of radiotherapy, chemotherapy and surgery to find a combination of them that improves life expectancy in patients diagnosed with pancreatic cancer. At the moment, numerous clinical trials are being conducted to evaluate preventive diagnostic procedures such as serological markers or perfecting available imaging tests. On the other hand, implementation of immunotherapy is being studied in a neoplasm that has lagged in the application of this procedure since present possible treatments do not substantially improve quality of life. Therefore, the purpose of our study is to summarize the main progresses that have been made in the diagnosis, treatment and screening of this disease, explaining the limitations that have been observed and analyzing future prospects in the management of this illness.

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

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.

[Chronic pancreatitis : Characterization and differentiation from pancreatic cancer]

Klinisches/methodisches Problem

Bei der chronischen Pankreatitis (CP) handelt es sich um eine langanhaltende Entzündung der Bauchspeicheldrüse, welche die normale Struktur und Funktion des Organs schädigt. Das breite Spektrum an entzündlichen Pankreaserkrankungen umfasst einzelne Entitäten, wie die fokale Pankreatitis (FP) oder den Pseudotumor („mass-forming pancreatitis“), welche radiomorphologisch ein Adenokarzinom der Bauchspeicheldrüse (PDAC) nachahmen können. In weiterer Folge kann eine Fehldiagnose zu einem vermeidbaren und unnötigen operativen Eingriff oder zu einer Therapieverzögerung führen.

Radiologische Standardverfahren

Der Ultraschall (US) ist das primäre bildgebende Verfahren zur Abklärung von Pankreaserkrankungen, gefolgt von kontrastmittelverstärkter Computertomographie (KM-CT), die als meistverwendete Methode bei der diagnostischen Abklärung von Bauchspeicheldrüsenerkrankungen gilt. Die Magnetresonanztomographie (MRT) und/oder die MR-Cholangiopankreatographie (MRCP) können als Problemlöser eingesetzt werden, um zwischen soliden und zystischen Läsionen zu unterscheiden sowie auch Anomalien der Pankreasgänge auszuschließen, welche bei rezidivierender akuter Pankreatitis (AP) vorhanden sein können, oder um frühe Anzeichen einer CP zu visualisieren. Die MRCP hat dabei die diagnostische endoskopische retrograde Cholangiopankreatographie (ERCP) in der Abklärung von therapeutischen Interventionen im Wesentlichen ersetzt.

Empfehlung für die Praxis

Folgender Übersichtsartikel fasst die relevanten Merkmale in der Computertomographie (CT) und MRT zusammen, um eine akkurate, frühzeitige Diagnose einer CP zu stellen und eine Differenzierung zwischen FP und Pankreaskarzinom zu ermöglichen, um somit – auch in schwierigen Fällen – ein adäquates Therapiemanagement zu gewährleisten.

The role of imaging in pelvic exenteration for gynecological cancers

Pelvic exenteration (PE) is one of the most challenging gynecologic oncologic surgeries and is an overriding term for different procedures that entail radical en bloc resection of the female reproductive organs and removal of additional adjacent affected pelvic organs (bladder, rectum, anus, etc.) with concomitant surgical reconstruction to restore bodily functions. Multimodality cross-sectional imaging with MRI, PET/CT, and CT plays an integral part in treatment decision-making, not only for the appropriate patient selection but also for surveillance after surgery. The purpose of this review is to provide a brief background on pelvic exenteration in gynecologic cancers and to familiarize the reader with the critical radiological aspects in the evaluation of patients for this complex procedure. The focus of this review will be on how imaging can aid in treatment planning and guide management.

[The microarchitecture of pancreatic cancer from the point of view of the pathologist and the radiologist]

Die diagnostische Radiologie ist gemeinsam mit der diagnostischen Pathologie eines der klinisch-morphologischen Fächer, welche in unterschiedlicher makroskopischer bzw. mikroskopischer Auflösung zur Detektion, Charakterisierung sowie zum Ausbreitungsmuster eines Tumors führen. Die klinischen Disziplinen sind oft voneinander getrennt, wenngleich es vor allem in klinischen Tumorboards immer stärkere Verzahnungen gibt. Am Beispiel des Pankreaskarzinoms sind die Korrelationen radiologischer und pathologischer Diagnostik dargestellt.

Imaging of Ampullary and Periampullary Conditions

The ampulla of Vater is formed by the union of the pancreatic duct and the common bile duct and is also known as hepatopancreatic ampulla or hepatopancreatic duct. The ampulla is surrounded by a muscular valve known as the sphincter of Oddi, which controls the flow of bile and pancreatic juices into the duodenum in response to food. The ampulla is also an important embryological landmark as it marks the anatomical transition from foregut to the midgut. Because of this, it is a watershed zone where the blood supply changes from the celiac axis to the superior mesenteric artery. Radiologic evaluation of the ampulla and the periampullary region is challenging because it requires an understanding of the embryology, the normal appearance, and different anatomic variants. Also, a wide variety of pathologies can occur in this region. The purpose of this review is to present the normal anatomy of the ampulla and the periampullary region on different imaging modalities and to summarize the imaging features of the common variants, and benign and malignant ampullary and periampullary conditions. Understanding of the normal anatomical appearance and variants along with the knowledge of common pathologic conditions affecting the ampulla and periampullary conditions can help radiologists in making accurate diagnosis resulting in optimum patient care.

Augmented Reality-Assisted Pancreaticoduodenectomy with Superior Mesenteric Vein Resection and Reconstruction

Introduction

Pancreaticoduodenectomy (PD) with superior mesenteric vein (SMV) reconstruction are often required to achieve complete (R0) resection for pancreatic head cancer (PHC) with tumor invasion of the SMV. Augmented reality (AR) technology can be used to assist in determining the extent of SMV involvement by superimposing virtual 3-dimensional (3D) images of the pancreas and regional vasculature on the surgical field.

Materials and Methods

Three patients with PHC and tumor invasion of the SMV underwent AR-assisted PD with SMV resection and reconstruction following preoperative computed tomography scanning. Preoperative imaging data were used to reconstruct 3D images of anatomical structures, including the tumor, portal vein (PV), SMV, and splenic vein (SV). Using AR software installed on a smart phone, the reconstructed 3D images were superimposed on the surgical field as viewed in a smart phone display to provide intermittent navigational assistance to the surgeon in identifying the boundaries of PHC tumor invasion for resection of the vessels involved.

Result

All patients successfully completed the operation. Intraoperative AR applications displayed virtual images of the pancreas, SMV, bile duct, common hepatic artery (CHA), and superior mesenteric artery (SMA). Two patients required end-to-end anastomosis for reconstruction of the SMV. One patient required allogenic vascular bypass to reconstruct the SMV-PV juncture with concomitant reconstruction of the SV-SMV confluence by end-to-side anastomosis of the SV and bypass vessel. Postoperative pathology confirmed R0 resections for all patients.

Conclusion

AR navigation technology based on preoperative CT image data can assist surgeons performing PD with SMV resection and reconstruction.

Impact of multidisciplinary approach and radiologic review on surgical outcome and overall survival of patients with pancreatic cancer: a retrospective cohort study

AIM

To evaluate the impact of multidisciplinary team case discussion including computed tomography (CT) radiologic review on surgical outcome and overall survival (OS) of patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Patients with PDAC evaluated in 2008-2011 and 2013-2016 (before and after multidisciplinary team introduction), aged <85 years and staged I-III, were included. Surgical failures and 2-year OS were compared in these periods. Available CT scans of preintervention period (2008-2011) cases were reviewed by two radiologists in consensus, assigning a resectability judgment to evaluate in how many cases a different recommendation would be achieved.

RESULTS

A total of 316 patients (49.3% female, age 71±10 years) were included: 132 in 2008-2011 and 184 in 2013-2016. The proportion of patients who underwent upfront surgery was similar in the two periods (51% vs 47% in 2008-2011 vs 2013-2016). Neoadjuvant referral increased from 7% to 21% and surgical resection was excluded for 42% patients in 2008-2011 vs 33% in 2013-2016 (p = 0.002). Adjusting by age, sex, and stage, surgical failures slightly decreased in 2013-2016 (odds ratio 0.89, 95% confidence interval 0.53-1.51); the decrease was stronger when therapeutic choice complied with CT indications (odds ratio 0.76, 95% confidence interval 0.36-1.63); in both cases, the decrease could be due to chance. After correction for age, sex, and stage, the hazard ratio of 2013-2016 for OS was 0.83 (95% confidence interval 0.64-1.09). In 33/114 (29%) patients, CT retrospective review produced a change in resectability judgment.

CONCLUSION

Although differences could be due to chance or generic improvement, the consistency between process and outcome indicators suggests that multidisciplinary team approach with radiologic review may improve outcomes.

[Radiologic Evaluation for Resectability of Pancreatic Adenocarcinoma]

Imaging studies play an important role in the detection, diagnosis, assessment of resectability, staging, and determination of patient-tailored treatment options for pancreatic adenocarcinoma. Recently, for patients diagnosed with borderline resectable or locally advanced pancreatic cancers, it is recommended to consider curative-intent surgery following neoadjuvant or palliative therapy, if possible. This review covers how to interpret imaging tests and what to consider when assessing resectability, diagnosing distant metastasis, and re-assessing the resectability of pancreatic cancer after neoadjuvant or palliative therapy.

Radiological evaluation of pancreatic cancer: What is the significance of arterial encasement >180° after neoadjuvant treatment?

PURPOSE

This study aimed to evaluate contrast-enhanced computed tomography (CE-CT) features for prediction of arterial tumor invasion in pancreatic cancer (PDAC) patients in the event of arterial encasement >180° after neoadjuvant (radio-)chemotherapy (NAT).

METHODS

Seventy PDAC patients with seventy-five arteries showing encasement >180° after completion of NAT were analyzed. All patients underwent surgical exploration with either tumor resection including arterial resection, periadventitial dissection (arterial divestment) or confirmation of locally irresectable disease. CE-CT scans were assessed regarding tumor extent and artery-specific imaging features. The results were analyzed on a per-artery basis. Based on the intraoperative and histopathological findings, encased arteries were classified as either invaded or non-invaded.

RESULTS

Eighteen radiologically encased arteries were resected; of these, nine had pathologic evidence for tumor invasion. In 42 encased arteries, the tumor could be removed by arterial divestment. In 13 patients with 15 encased arteries, the tumor was deemed technically irresectable. Median tumor size, length of solid soft tissue contact, and degree of circumferential contiguity by solid soft tissue along the artery in CE-CT were significantly lower in the non-invaded than in the invaded artery group (p ≤ 0.017). Imaging features showed moderate accuracies for prediction of arterial invasion (≤72.0 %). The thresholds ≤26 mm for post-NAT solid soft tissue contact and ≤270° for circumferential contiguity by solid soft tissue had high negative predictive values (≥87.5 %).

CONCLUSION

Although post-NAT prediction of arterial invasion remains difficult, arteries with ≤270° contiguity by soft tissue and arteries with ≤26 mm length of solid soft tissue contact are unlikely to be invaded, with possible implications for surgical planning.

CT texture analysis for the presurgical prediction of superior mesenteric-portal vein invasion in pancreatic ductal adenocarcinoma: comparison with CT imaging features

AIM

To investigate the value of computed tomography (CT) texture analysis (TA) and imaging features for evaluating suspected surgical superior mesenteric-portal vein (SMPV) invasion in patients with pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

Fifty-four patients with PDAC in the pancreatic head or uncinate process with suspected SMPV involvement were analysed retrospectively. SMPV invasion status was identified by surgical exploration. For each patient, 396 texture features were extracted on pretreatment CT. Non-parametric tests and minimum redundancy maximum relevance were used for feature selection. A CTTA model was constructed using multivariate logistic regression, and the area under the receiver operating characteristic (AUROC) of the model was calculated. Two reviewers evaluated qualitative imaging features independently for SMPV invasion and interobserver agreement was investigated. The diagnostic performance of the imaging features and the CTTA model for SMPV invasion was compared using the McNemar test.

RESULTS

Of the 54 patients with PDAC, SMPV invasion was detected in 23 (42.6%). The CTTA model yielded an AUROC of 0.88 (95% confidence interval, 0.76-0.97) and achieved significantly higher specificity (0.90) than the two reviewers (0.61 and 0.65; p=0.027 and 0.043). Interobserver agreement was moderate between the two reviewers (κ = 0.517). Of the 13 cases with disagreement between the two reviewers, 11 cases were predicted accurately by the CTTA model.

CONCLUSION

CTTA can predict suspected SMPV invasion in PDAC and may be a beneficial addition for qualitative imaging evaluation.

Hyperechoic Periappendiceal Fat: Evaluation of Criteria for Improving Specificity in the Sonographic Diagnosis of Appendicitis in Pediatric Patients

OBJECTIVES

To test the hypothesis that abutting and encasing types of hyperechoic periappendiceal fat are specific sonographic indicators of appendicitis in pediatric patients, including individuals with maximum outer diameters (MODs) of 6 to 8 mm in whom diagnosis by the MOD alone is known to be equivocal.

METHODS

Appendiceal sonograms of 271 consecutive pediatric patients were retrospectively evaluated for hyperechoic periappendiceal fat (globular, ≥1.0 cm; categorized as type 0, none; type 1, "abutting," encompassing <180° of the appendiceal circumference; or type 2, "encasing," encompassing 180° or more of the appendiceal circumference) and the MOD. Histopathologic and medical records constituted reference standards. Statistical methods included the binomial distribution, logistic regression, a receiver operating characteristic analysis, and the exact McNemar test.

RESULTS

All patients with hyperechoic fat and 105 of 107 patients with appendicitis had MODs of 6 mm or greater. The MOD and fat types 1 and 2 each were significantly associated with appendicitis in the univariable regression. The MOD and fat type 1 were independently associated with appendicitis in multivariable regression (odds ratio, 24.97; P = .034; and odds ratio, 5.35; P < .001, respectively). Specificities of an MOD of 6 to 8 mm and an MOD of 6 mm or greater alone were 89.0% (95% confidence interval, 83.2%-93.4%); these increased to 100.0% each (95% confidence interval, 97.8%-100.0%; P < .001) when combined with fat types 1, 2, and either 1 or 2 as diagnostic criteria, with positive predictive values of 100.0%.

CONCLUSIONS

Types 1 and 2 periappendiceal fat are specific indicators of appendicitis, and both improve specificity compared to the MOD. Importantly, they add specificity in diagnosing appendicitis in patients with diagnostically equivocal MODs of 6 to 8 mm.

Neoadjuvant and Adjuvant Therapy in Operable Pancreatic Cancer: Both Honey and Milk (but No Bread?)

Pancreatic cancer has a dismal prognosis. Resection is the best option for cure, supported by multimodal therapy to treat the systemic disease. While adjuvant therapy has become standard in those who are fit and who can tolerate the given regimen, the concept of perioperative (neoadjuvant) therapy is building momentum. The concepts of “borderline” and “locally advanced” have changed the previous dichotomized “resectable/non-resectable” into subcategories for which new algorithms have emerged, with neoadjuvant therapy discussed both for upfront resectable pancreatic cancer, for those deemed borderline resectable, and as “induction or conversion” therapy for locally advanced disease. The purpose of this invited commentary is to discuss some of the changing paradigms in multimodal therapy for operable pancreatic cancer. The PREOPANC trial presented randomized data on the role of neoadjuvant therapy for resectable and borderline cancers, but new questions have emerged. The role of combination therapy in the preoperative setting is discussed in the light of this trial. FOLFIRINOX has emerged as the most potent treatment regimen in the metastatic and adjuvant setting, but with no level I data to support neoadjuvant use yet. Several trials are ongoing to arrive at the best answer.

Radiographic Response of Vessel Involvement and Resectability After Neoadjuvant Chemoradiation in Patients With Locally Advanced Pancreatic Cancer

OBJECTIVES

Survival of patients with locally advanced pancreatic cancer (LAPC) is improved when neoadjuvant chemoradiation enables subsequent surgical resection. Here, the authors assess changes in vessel involvement as a possible indicator of resectability.

METHODS

Pancreatic gross tumor and all major abdominal vessels were contoured for 49 patients with unresectable LAPC before and after neoadjuvant chemoradiation. Changes were compared by paired t tests. Tumor-vessel relationships were automatically quantified using Medical Imaging Interaction Toolkit and examined for correlation with resectability and outcome.

RESULTS

Tumor volumes were significantly reduced by chemoradiation (41 to 33 mL, P<0.0001). Maximum circumferential vessel involvement decreased for most patients and was statistically significant for the superior mesenteric (P<0.003) and splenic veins (P<0.038). Resection was possible in some patients and correlated positively with survival (28 vs. 15 mo, r=0.40), a decrease in CA 19.9 levels (r=0.48), and reduced involvement of most vessels. Nevertheless, surgical resection with a successful detachment of tumor tissue from major vessels was also achieved in some patients who did not show improvement in radiographic vessel involvement, but rather a reduction in tumor volume and CA 19.9 levels.

CONCLUSIONS

The present analysis demonstrates that neoadjuvant chemoradiation can enable subsequent surgical resection in patients with LAPC. Complete resection substantially prolongs survival. Therefore, surgical exploration should be offered if vessel involvement is improved by chemoradiation and considered in radiographic unchanged vessel involvement if size and CA 19.9 levels decrease, as these factors may indicate resectable disease, too.

Clinical Impact of 18F-FDG PET/CT in the Diagnostic Workup of Pancreatic Ductal Adenocarcinoma: A Systematic Review

In this review, the performance of fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in the diagnostic workup of pancreatic ductal adenocarcinoma (PDAC) is evaluated. A comprehensive literature search up to September 2020 was performed, selecting studies with the presence of: sample size ≥10 patients and index test (i.e., “FDG” or “18F-FDG” AND “pancreatic adenocarcinoma” or “pancreas cancer” AND “PET” or “positron emission tomography”). The methodological quality was evaluated using the revised quality assessment of diagnostic accuracy studies (QUADAS-2) tool and presented according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Basic data (authors, year of publication, country and study design), patients’ characteristics (number of enrolled subjects and age), disease phase, type of treatment and grading were retrieved. Forty-six articles met the adopted research criteria. The articles were divided according to the considered clinical context. Namely, besides conventional anatomical imaging, such as computed tomography (CT) and magnetic resonance imaging (MRI), molecular imaging with FDG PET/CT is an important tool in PDAC, for all disease stages. Further prospective studies will be necessary to confirm the cost-effectiveness of such imaging techniques by testing its real potential improvement in the clinical management of PDAC.

Radiomics-Assisted Presurgical Prediction for Surgical Portal Vein-Superior Mesenteric Vein Invasion in Pancreatic Ductal Adenocarcinoma

Objectives

To develop a radiomics signature for predicting surgical portal vein-superior mesenteric vein (PV-SMV) in patients with pancreatic ductal adenocarcinoma (PDAC) and measure the effect of providing the predictions of radiomics signature to radiologists with different diagnostic experiences during imaging interpretation.

Methods

Between February 2008 and June 2020, 146 patients with PDAC in pancreatic head or uncinate process from two institutions were retrospectively included and randomly split into a training (n = 88) and a validation (n =58) cohort. Intraoperative vascular exploration findings were used to identify surgical PV-SMV invasion. Radiomics features were extracted from the portal venous phase CT images. Radiomics signature was built with a linear elastic-net regression model. Area under receiver operating characteristic curve (AUC) of the radiomics signature was calculated. A senior and a junior radiologist independently review CT scans and made the diagnosis for PV-SMV invasion both with and without radiomics score (Radscore) assistance. A 2-sided Pearson's chi-squared test was conducted to evaluate whether there was a difference in sensitivity, specificity, and accuracy between the radiomics signature and the unassisted radiologists. To assess the incremental value of providing Radscore predictions to the radiologists, we compared the performance between unassisted evaluation and Radscore-assisted evaluation by using the McNemar test.

Results

Numbers of patients identified as presence of surgical PV-SMV invasion were 33 (37.5%) and 19 (32.8%) in the training and validation cohort, respectively. The radiomics signature achieved an AUC of 0.848 (95% confidence interval, 0.724-0.971) in the validation cohort and had a comparable sensitivity, specificity, and accuracy as the senior radiologist in predicting PV-SMV invasion (all p-values > 0.05). Providing predictions of radiomics signature increased both radiologists' sensitivity in identifying PV-SMV invasion, while only the increase of the junior radiologist was significant (63.2 vs 89.5%, p-value = 0.025) instead of the senior radiologist (73.7 vs 89.5%, p-value = 0.08). Both radiologists' accuracy had no significant increase when provided radiomics signature assistance (both p-values > 0.05).

Conclusions

The radiomics signature can predict surgical PV-SMV invasion in patients with PDAC and may have incremental value to the diagnostic performance of radiologists during imaging interpretation.

Evaluation of contrast-enhanced computed tomography for the differential diagnosis of hypovascular pancreatic neuroendocrine tumors from chronic mass-forming pancreatitis

PURPOSE

To assess the role of contrast-enhanced computed tomography (CECT) for differentiation of hypovascular pancreatic neuroendocrine tumors (hypo-PNETs) from chronic mass-forming pancreatitis (CMFP).

METHODS

A retrospective study of 59 patients (27 hypo-PNETs patients vs 32 CMFP patients) who underwent preoperative CECT between July 2012 and July 2019 was performed. Qualitative and quantitative analysis was performed, including mass location, size, margin, cystic changes, calcification, pancreatic or bile duct dilatation, pancreatic atrophy, local vessels involvement, mass contrast enhancement and mass-to-pancreas enhancement ratio. Multivariate logistic regression analyses were used to identify relevant CT imaging findings in differentiation between hypo-PNETs and CMFP.

RESULTS

When compared to CMFP, hypo-PNETs more frequently had a well-defined margin and cystic changes and less frequently had a history of pancreatitis and calcification. CMFP had higher mass contrast enhancement and mass-to-pancreas enhancement ratio in the portal and delayed phases than hypo-PNETs. After multivariate logistic regression analyses, areas under the curve (AUCs) were 0.795 (95 % CI: 0.652-0.899), 0.752 (95 % CI: 0.604-0.866), 0.859 (95 % CI: 0.726-0.943), and 0.929 (95 % CI: 0.814-0.983) for Model 1(clinical factors), Model 2 (qualitative parameters), Model 3 (quantitative parameters), and their combinations, respectively.

CONCLUSION

Combined assessment of clinical factors, qualitative, and quantitative imaging characteristics can improve the differentiation between hypo-PNETs and CMFP at CECT.

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.

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.

A New Score to Predict the Resectability of Pancreatic Adenocarcinoma: The BACAP Score

Surgery remains the only curative treatment for pancreatic ductal adenocarcinoma (PDAC). Therefore, a predictive score for resectability on diagnosis is needed. A total of 814 patients were included between 2014 and 2017 from 15 centers included in the BACAP (the national Anatomo-Clinical Database on Pancreatic Adenocarcinoma) prospective cohort. Three groups were defined: resectable (Res), locally advanced (LA), and metastatic (Met). Variables were analyzed and a predictive score was devised. Of the 814 patients included, 703 could be evaluated: 164 Res, 266 LA, and 273 Met. The median ages of the patients were 69, 71, and 69, respectively. The median survival times were 21, 15, and nine months, respectively. Six criteria were significantly associated with a lower probability of resectability in multivariate analysis: venous/arterial thrombosis (p = 0.017), performance status 1 (p = 0.032) or ≥ 2 (p = 0.010), pain (p = 0.003), weight loss ≥ 8% (p = 0.019), topography of the tumor (body/tail) (p = 0.005), and maximal tumor size 20-33 mm (p < 0.013) or >33 mm (p < 0.001). The BACAP score was devised using these criteria (http://jdlp.fr/resectability/) with an accuracy of 81.17% and an area under the receive operating characteristic (ROC) curve of 0.82 (95% confidence interval (CI): 0.78; 0.86). The presence of pejorative criteria or a BACAP score < 50% indicates that further investigations and even neoadjuvant treatment might be warranted. Trial registration: NCT02818829.

Three-Dimensional Fixation: Pathological Protocol Following Pancreaticoduodenectomy with Portal Vein Resection for Pancreatic Cancer

BACKGROUND

Although existing histopathologic protocols for pancreatic cancer have been standardized, the relevance between prognosis and resection margin clearance is still controversial. Reconstruction of specimens as in situ to appropriately assess the margin is desirable in these protocols.

METHODS

The three-dimensional fixation protocol defined specimen handling of pancreaticoduodenectomy (PD) with portal vein (PV) resection. The superior mesenteric artery (SMA) margin of the specimen was tidily fixed around an artificial SMA as if in an in situ setting. In this prospective study, patients undergoing PD with PV resection for pancreatic cancer in 2016 were enrolled. To evaluate the feasibility of the three-dimensional fixation protocol, the SMA margin distance and PV involvement of tumor assessed by computed tomography (CT) were compared with those assessed by pathology.

RESULTS

Thirty-three patients with/without preoperative chemotherapy were enrolled. The entire cohort did not present with high-quality diagnostic assessment of the medial margins around SMA and PV (correct estimation, 58% and 73%, respectively). In contrast, in 16 patients undergoing upfront surgery, the concordance value of the SMA margin, which assesses the agreement between CT and pathology measures, was 0.48 (moderate agreement). The PV involvement examined by imaging was significantly associated with that by pathology (P = 0.013).

CONCLUSIONS

The three-dimensional fixation protocol was applicable to all cases undergoing PD with PV resection. Focusing on the patients with upfront surgery demonstrated the feasibility of accurate pathological assessment of medial margins. We propose this protocol as a promising standard for the assessment of true surgical margin status.

Impact of structured report on the quality of preoperative CT staging of pancreatic ductal adenocarcinoma: assessment of intra- and inter-reader variability

PURPOSE

To evaluate whether a structured radiology report improves the completeness of preoperative CT staging of pancreatic ductal adenocarcinoma (PDA) compared to conventional free-text reports.

METHODS

We retrospectively included 27 patients (mean age, 64 ± 11.1 years) referred for pancreatic preoperative CT scan for staging of PDA between 2015 and 2018 and in whom a diagnosis of pancreatic adenocarcinoma was ultimately confirmed. Four readers independently reported CT scans with both conventional free-text and structured reports. Differences in reported morphologic and vascular features with the two reports were assessed through McNemar Test. Intra-reader and inter-reader were calculated.

RESULTS

A total of 216 reports were completed by four different readers including 108 free-text and 108 structured reports. Overall, 139 of 540 morphologic characteristics of PDA and 869 of 1188 vascular key features were only described in structured reports. Encasement of left gastric artery, gastroduodenal artery and splenic artery was described in up to 14.8% using free-text reports and in up to 29.6% using structured report, resulting in low-intra-reader agreement (k = 0.033-0.216). Inter-reader agreement improved with structured report compared to free-text one for left gastric artery (ICC = 0.844 vs. ICC = 0.493, respectively), gastroduodenal artery (ICC = 0.730 vs. ICC = 0.449, respectively), portal vein (ICC = 0.847 vs. ICC = 0.638, respectively), portal confluence (ICC = 0.848 vs. ICC = 0.422, respectively) superior mesenteric vein (ICC = 0.765 vs. ICC = 0.695, respectively), and splenic vein (ICC = 0.921 vs. ICC = 0.841, respectively).

CONCLUSION

Structured reports for PDA staging significantly reduces the number of missing morphological and vascular features of PDA and improves the inter-reader agreement compared to free-text reports.

Cachectic Body Composition and Inflammatory Markers Portend a Poor Prognosis in Patients with Locally Advanced Pancreatic Cancer Treated with Chemoradiation

BACKGROUND

Patients with pancreatic cancer often develop cancer cachexia, a complex multifactorial syndrome with weight loss, muscle wasting and adipose tissue depletion with systemic inflammation causing physical impairment. In patients with locally advanced pancreatic cancer (LAPC) neoadjuvant treatment is routinely performed to allow a subsequent resection. Herein, we assess body composition and laboratory markers for cancer cachexia both before and after neoadjuvant chemoradiation (CRT).

METHODS

Subcutaneous fat (SCF), visceral fat (VF), skeletal muscle (SM), weight and laboratory parameters were determined longitudinally in 141 LAPC patients treated with neoadjuvant CRT. Changes during CRT were statistically analyzed and correlated with outcome and Kaplan-Meier curves were plotted. Different prognostic factors linked to cachexia were assessed by uni- and multivariable cox proportional hazards models.

RESULTS

There was a significant decrease in weight as well as SCF, VF and SM during CRT. The laboratory parameter C-reactive protein (CRP) increased significantly, whereas there was a significant decrease in leukocyte count, hemoglobin, albumin and cholinesterase as well as in the tumor marker CA 19.9. Cachectic weight loss, sarcopenia, reductions in body compartments SCF, VF and SM, and changes in laboratory markers as well as resection affected survival in univariable analysis. In multivariable analysis, weight loss >5% (HR 2.8), reduction in SM >5% (HR 5.5), an increase in CRP (HR 2.2) or CA 19.9 (HR 1.9), and resection (HR 0.4) remained independently associated with survival, whereas classical cachexia and sarcopenia did not. Interestingly, the subgroup of patients with cachectic weight loss >5% or SM reduction >5% during CRT did not benefit from resection (median survival 12 vs. 27 months).

CONCLUSIONS

Persistent weight loss and muscle depletion during CRT as well as systemic inflammation after CRT impacted survival more than cachexia or sarcopenia according classical definitions.

Macrophage-derived exosomal microRNA-501-3p promotes progression of pancreatic ductal adenocarcinoma through the TGFBR3-mediated TGF-β signaling pathway

Background

Exosomes from cancer cells or immune cells, carrying bio-macromolecules or microRNAs (miRNAs), participate in tumor pathogenesis and progression by modulating microenvironment. Our study aims to investigate the role of these microRNA-501-3p (miR-501-3p) containing exosomes derived from tumor-associated macrophage (TAM) in the progression of pancreatic ductal adenocarcinoma (PDAC).

Methods

Firstly, the function of TAM recruitment in PDAC tissues was assessed, followed by identification of the effects of M2 macrophage-derived exosomes on PDAC cell activities and tumor formation and metastasis in mice. In silico analysis was conducted to predict differentially expressed genes and regulatory miRNAs related to PDAC treated with macrophages, which determined miR-501-3p and TGFBR3 for subsequent experiments. Next, gain- and loss-of-function experiments were performed to examine their role in PDAC progression with the involvement of the TGF-β signaling pathway.

Results

TAM recruitment in PDAC tissues was associated with metastasis. Highly expressed miR-501-3p was observed in PDAC tissues and TAM-derived exosomes. Both M2 macrophage-derived exosomes and miR-501-3p promoted PDAC cell migration and invasion, as well as tumor formation and metastasis in nude mice. MiR-501-3p was verified to target TGFBR3. PDAC cells presented with down-regulated TGFBR3, which was further decreased in response to M2 macrophage treatment. TGF-β signaling pathway activation was implicated in the promotion of miR-501-3p in PDAC development. The suppression of macrophage-derived exosomal miR-501-3p resulted in the inhibition of tumor formation and metastasis in vivo.

Conclusion

M2 macrophage-derived exosomal miR-501-3p inhibits tumor suppressor TGFBR3 gene and facilitates the development of PDAC by activating the TGF-β signaling pathway, which provides novel targets for the molecular treatment of PDAC.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1313-x) contains supplementary material, which is available to authorized users.

Preoperative CT findings for prediction of resectability in patients with gallbladder cancer

OBJECTIVES

To predict residual tumor (R) classification in patients with a surgery for gallbladder (GB) cancer, using preoperative CT.

METHODS

One hundred seventy-three patients with GB cancer who underwent CT and subsequent surgery were included. Two radiologists assessed CT findings, including tumor morphology, location, T stage, adjacent organ invasion, hepatic artery (HA) invasion, portal vein invasion, lymph node metastasis, metastasis, resectability, gallstone, and combined cholecystitis. The R classification was categorized as no residual tumor (R0) and residual tumor (R1 or R2). We analyzed the correlation between CT findings and R classification. We also followed up the patients as long as five years and analyzed the relationship between the R classification and the overall survival (OS).

RESULTS

There were 134 patients with R0 and 39 patients with R1/R2. On multivariable analysis, liver invasion (Exp(B) = 3.19, p = 0.010), bile duct invasion (Exp(B) = 3.69, p = 0.031), and HA invasion (Exp(B) = 3.74, p = 0.039) were independent, significant predictors for residual tumor. When two of these three criteria were combined, the accuracy for predicting a positive resection margin was 83.38% with a specificity of 93.28%. The OS and the median patient survival time differed significantly according to the resection margin, i.e., 56.0% and 134.4 months in the R0 resection and 5.1% and 10.8 months in the R1/R2 resection group (p < 0.001).

CONCLUSIONS

Preoperative CT findings could aid in planning surgery and determining the resectability using the high-risk findings of residual tumor, including liver invasion, bile duct invasion, and HA invasion.

KEY POINTS

• Liver invasion, bile duct invasion, and HA invasion were significant preoperative CT predictors for residual tumor in GB cancer. • HA invasion showed the highest OR on multivariate analysis and the highest predictor point on a nomogram for predicting a positive resection margin. • Association of two factors can predict positive resection margin with an accuracy of 83.38% and a specificity of 93.28%.