Computed Tomography Enhancement Pattern of the Pancreatic Parenchyma Predicts Postoperative Pancreatic Fistula After Pancreaticoduodenectomy

Comparing the distal pancreatectomy fistula risk score (D-FRS) and DISPAIR-FRS for predicting pancreatic fistula after distal pancreatectomy

BACKGROUNDS

Distal pancreatectomy fistula risk score (D-FRS) and DISPAIR-FRS has not been widely validated for predicting postoperative pancreatic fistula (POPF) after distal pancreatectomy (DP).

METHODS

We retrospectively analysed 104 patients undergoing DP. The predictive value of the D-FRS and DISPAIR-FRS were compared. Risk factors associated with POPF were investigated by multivariate analysis.

RESULTS

Of the 104 patients, 23 (22.1%) were categorized into the POPF group (all grade B). The areas under the ROC (AUCs) of the D-FRS (preoperative), D-FRS (intraoperative), and DISPAIR-FRS were 0.737, 0.809, and 0.688, respectively. Stratified by the D-FRS (preoperative), the POPF rates in low-risk, intermediate-risk, and high-risk groups were 5%, 22.6%, and 36.4%, respectively. By the D-FRS (intraoperative), the POPF rates in low-risk, intermediate-risk, and high-risk groups were 8.8%, 47.1%, and 47.4%, respectively. By the DISPAIR-FRS, the POPF rates in low-risk, intermediate-risk, and extreme-high-risk groups were 14.8%, 23.8% and 62.5%, respectively. Body mass index and main pancreatic duct diameter were independent risk factors of POPF both in preoperative (P = 0.014 and P = 0.033, respectively) and intraoperative (P = 0.015 and P = 0.039) multivariate analyses.

CONCLUSION

Both the D-FRS (preoperative), D-FRS (intraoperative), and DISPAIR-FRS has good performance in POPF prediction after DP. The risk stratification was not satisfactory in current Asian cohort.

Postoperative computed tomography findings predict re-drainage cases after early drain removal in pancreaticoduodenectomy

PURPOSE

This study aimed to investigate the risk factors for re-drainage in patients with early drain removal after pancreaticoduodenectomy (PD).

METHODS

This study retrospectively analyzed 114 patients who underwent PD and prophylactic drain removal on postoperative day (POD) 4 between January 2012 and March 2021. We analyzed the risk factors for re-drainage according to various factors. Peri-pancreaticojejunostomic fluid collection (PFC) index and pancreatic cross-sectional area (CSA) were evaluated using computed tomography on POD 4. The PFC index was calculated by multiplying the length, width, and height at the maximum aspect.

RESULTS

Among the 114 patients, 15 (13%) underwent re-drainage due to postoperative pancreatic fistula. Multivariate analysis identified a PFC index ≥ 8.16 cm3 on POD 4 (odds ratio [OR], 20.40, 95%CI 2.38-174.00; p = 0.006) and pancreatic CSA on POD 4 ≥ 3.65 cm2 (OR, 16.40, 95%CI 1.57-171.00; p = 0.020) as independent risk factors for re-drainage.

CONCLUSION

A careful decision might be necessary for early drain removal in patients with a PFC index ≥ 8.16 cm3 and pancreatic CSA ≥ 3.65 cm2.

Radiological parameters to predict pancreatic texture: Current evidence and future perspectives

Preoperative prediction of the postoperative pancreatic fistula risk is critical in the current era of minimally invasive pancreatic surgeries to tailor perioperative management, thereby minimizing postoperative morbidity. Pancreatic duct diameter can be readily measured by any routine imaging used to diagnose pancreatic disease. However, radiological evaluation of pancreatic texture, an important determinant of pancreatic fistula, has not been widely used to predict the risk of postoperative pancreatic fistula. Qualitative and quantitative assessment of pancreatic fibrosis and fat fraction provides the basis for predicting pancreatic texture. Traditionally computed tomography has been utilized in identifying and characterizing pancreatic lesions and background parenchymal pathologies. With the increasing utilisation of endoscopic ultrasound and magnetic resonance imaging for evaluating pancreatic pathologies, elastography is emerging as a promising tool for predicting pancreatic texture. Also, recent studies have shown that early surgery for chronic pancreatitis is associated with better pain relief and preservation of pancreatic function. Pancreatic texture assessment can allow early diagnosis of chronic pancreatitis, facilitating early intervention. The present review outlines the current evidence in utilizing various imaging modalities for determining the pancreatic texture based on different parameters and image sequences. However, multidisciplinary investigations using strong radiologic-pathologic correlation are needed to standardize and establish the role of these non-invasive diagnostic tools in predicting pancreatic texture.

Histological pancreatic findings correlate with computed tomography attenuation and predict postoperative pancreatic fistula following pancreatoduodenectomy

BACKGROUND

Although a soft pancreas is a widely-accepted reliable risk factor for postoperative pancreatic fistula (POPF) after pancreatoduodenectomy (PD), there is no established preoperative evaluation of pancreatic texture.

METHODS

Two hundred thirty-seven patients who underwent PD with histological pancreatic assessment were retrospectively enrolled. The degree of fibrosis and fatty infiltration was scored histologically as seven grades and five grades, respectively. Computed tomography (CT) attenuation of the pancreas was measured on preoperative unenhanced CT images. Correlations between the CT attenuation of the pancreas and the histological pancreatic findings, and the development of POPF were analyzed.

RESULTS

The fibrosis grade was significantly higher for hard pancreas than for soft pancreas (p < 0.001), whereas the fatty infiltration grade was similar between the two types (p = 0.161). CT attenuation of the pancreas was inversely correlated with both fibrosis grade (Spearman's rank correlation coefficient ([r] = -0.609, p < 0.001) and fatty infiltration grade (r = -0.382, p < 0.001). Multivariate analysis showed that body mass index ≥25 kg/m² (odds ratio [OR]: 5.64, p < 0.001) and fibrosis grade ≤2 (OR: 18.0, p < 0.001) were independent risk factors for clinically significant POPF.

CONCLUSION

Histological pancreatic texture can be evaluated with CT attenuation and might be helpful in preoperatively predicting the development of POPF after PD.

Do preoperative pancreatic computed tomography attenuation index and enhancement ratio predict pancreatic fistula after pancreaticoduodenectomy?

BACKGROUND

The commonly used predictors of clinically relevant postoperative pancreatic fistula (CR-POPF) following pancreaticoduodenectomy (PD) have subjective assessment components and can be used only in the postoperative setting. Also, the available objective predictors based on preoperative cross-sectional imaging were not prospectively studied.

AIM

To evaluate the accuracy of the pancreatic attenuation index (PAI) and pancreatic enhancement ratio (PER) for predicting CR-POPF following PD and its correlation with pancreatic fat fraction and fibrosis.

METHODS

A prospective observational study included patients who underwent PD for benign and malignant pathology of the periampullary region or pancreatic head between February 2019 and February 2021. Patients undergoing extended or total pancreatectomy and those with severe atrophy of pancreatic tissue or extensive parenchymal calcifications in the pancreatic head and neck precluding calculation of PAI and PER were excluded from the study. Preoperatively PAI was measured in the neck of the pancreas by marking regions of interest (ROI) in the non-contrast computed tomography (CT), and PER was measured during the contrast phase of the CT abdomen. Also, the fibrosis score and fat fraction of the pancreatic neck were assessed during the histopathological examination. Demographic, clinical and preoperative radiological indices (PAI, PER) were evaluated to predict CR-POPF. Preoperative pancreatic neck CT indices were correlated with the histopathological assessment of fat fraction and fibrosis.

RESULTS

Of the 70 patients who underwent PD, 61 patients fulfilling the inclusion criteria were included in the analysis. The incidence of CR-POPF was 29.5% (18/61). PAI had no association with the development of CR-POPF. Of the preoperative parameters, PER (mean ± standard deviation [SD]) was significantly lower in patients developing CR-POPF (0.58 ± 0.20 vs 0.81 ± 0.44, P = 0.006). The area under the curve for the PER was 0.661 (95%CI: 0.517-0.804), which was significant (P = 0.049). PER cut-off of 0.673 predicts CR-POPF with 77.8% sensitivity and 55.8% specificity. PAI and PER had a weak negative correlation (Strength-0.26, P = 0.037). Also, PER showed a moderately positive correlation with fibrosis (Strength 0.50, P < 0.001). Patients with CR-POPF had a significantly higher incidence of the intraabdominal abscess (50% vs 2.3%, P < 0.001), delayed gastric emptying (83.3% vs 30.2, P < 0.001), and prolonged mean (± SD) postoperative hospital stay (26.8 ± 13.9 vs 9.6 ± 3.6, P = 0.001).

CONCLUSION

PER exhibited good accuracy in predicting the development of CR-POPF. PER additionally showed a good correlation with PAI and fibrosis scores and may be used as an objective preoperative surrogate for assessing pancreatic texture. However, ROI-based PAI did not show any association with CR-POPF and pancreatic fat fraction.

A modified alternative fistula risk score (a-FRS) obtained from the computed tomography enhancement pattern of the pancreatic parenchyma predicts pancreatic fistula after pancreatoduodenectomy

BACKGROUND

Alternative fistula risk score (a-FRS) is useful to predict clinically relevant postoperative pancreatic fistula (CR-POPF) after pancreatoduodenectomy (PD).

METHODS

Clinical data from 239 patients undergoing PD were collected. The CT value of the pancreatic parenchyma was measured in the nonenhanced (N), arterial (A), portal venous (P), and late (L) phases. The A/N, A/P, P/L and A/L ratios were calculated and their correlation with CR-POPF were analyzed. By replacing pancreatic texture with the best CT attenuation ratio, a modified a-FRS was developed.

RESULTS

Forty-seven patients developed CR-POPF. The A/P ratio (P < 0.001), P/L ratio (P = 0.002) and A/L ratio (P < 0.001) were significantly higher in the CR-POPF group. The A/L ratio performed best in predicting CR-POPF (AUC: 0.803) and the cut-off value is 1.36. A/L ratio >1.36 (P < 0.001), body mass index (P = 0.005) and duct diameter (P = 0.037) were independently associated with CR-POPF. By replacing soft texture with an A/L ratio >1.36, a modified a-FRS was developed and performed better than the a-FRS (AUC: 0.823 vs 0.748, P = 0.006) in predicting CR-POPF.

CONCLUSIONS

The modified a-FRS is an objective and preoperative model for predicting the occurrence of CR-POPF after PD.

Estimated functional remnant pancreatic volume predicts nonalcoholic fatty liver disease after pancreaticoduodenectomy: use of computed tomography attenuation value of the pancreas

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a late complication of pancreaticoduodenectomy (PD). However, this complication is difficult to predict preoperatively. This study aimed to assess the association between NAFLD and preoperative computed tomography (CT) findings.

METHODS

Medical records of 112 patients who had undergone PD and had CT scans preoperatively and 6 months postoperatively were retrospectively reviewed. We evaluated several CT findings, including the CT attenuation value of the remnant pancreas, remnant pancreatic volume (RPV), and the estimated functional remnant pancreatic volume (eFRPV) on preoperative CT. The variables, including the CT findings and histopathological findings, were compared between the patients with and without NAFLD after PD.

RESULTS

The NAFLD group included 21 patients (18.8%). The CT attenuation value of the remnant pancreas was correlated with the pancreatic acinar cell density (r = 0.537), and was lower in the NAFLD group than in the non-NAFLD group (p = 0.007). The eFRPV was lower in the NAFLD group than in the non-NAFLD group (p = 0.002). An eFRPV ≤47 mL·HU was an independent predictive factor for NAFLD (p = 0.007; odds ratio: 6.73; 95% confidence interval: 1.70-26.70).

CONCLUSION

The eFRPV can be used to preoperatively predict NAFLD after PD.

Preoperative prediction of clinically relevant postoperative pancreatic fistula after pancreaticoduodenectomy

OBJECTIVES

To develop a radiomics model and a combined model for preoperative prediction of clinically relevant postoperative pancreatic fistula (CR-POPF) in patients undergoing pancreaticoduodenectomy and to compare the predictive performance of the two models with the traditional Fistula Risk Score system.

METHODS

A total of 250 patients who underwent pancreaticoduodenectomy (PD) with preoperative computed tomography (CT) were divided into a training set (n = 175) and validation set (n = 75). The pancreatic area was automatically segmented on the portal venous phase CT images using a 3D U-Net segmentation model. A radiomics model was developed using radiomics features extracted from the volume of interest (VOI) and a combined model was developed using radiomics features, demographic information and radiological features. The FRS was also used to predict POPF. The predictive performance of the prediction models was assessed using receiver operating characteristic (ROC) curves, calibration curves and decision curve analysis (DCA).

RESULTS

Eleven and 18 features were extracted for the radiomics model and combined model, respectively. The combined model showed excellent predictive value, with an AUC of 0.871 (95 %CI 0.816,0.926) and 0.869 (95 %CI 0.779,0.958) in the training cohort and validation cohort, respectively. Calibration curves and DCA showed that the combined model outperformed the traditional FRS system and radiomics model.

CONCLUSION

The combined model exhibited excellent predictive performance and outperformed the traditional FRS system and radiomics model in the preoperative prediction of CR-POPF.

Systematic review and meta-analysis of factors associated with post-operative pancreatic fistula following pancreatoduodenectomy

BACKGROUND

Many studies have explored factors relating to post-operative pancreatic fistula (POPF); however, the original definition (All-POPF) was revised to include only 'clinically relevant' (CR) POPF. This study identified variables associated with the two International Study Group on Pancreatic Surgery definitions to identify which variables are more strongly associated with CR-POPF.

METHODS

A systematic review identified all studies reporting risk factors for POPF (using both International Study Group on Pancreatic Fistula definitions) following pancreatoduodenectomy. The primary outcome was factors associated with CR-POPF. Meta-analyses (random effects models) of pre-, intra- and post-operative factors associated with POPF in more than two studies were included.

RESULTS

Among 52 774 patients All-POPF (n = 69 studies) and CR-POPF (n = 53 studies) affected 27% (95% confidence interval (CI_95% ) 23-30) and 19% (CI_95% 17-22), respectively. Of the 176 factors, 24 and 17 were associated with All- and CR-POPF, respectively. Absence of pre-operative pancreatitis, presence of renal disease, no pre-operative neoadjuvant therapy, use of post-operative somatostatin analogues, absence of associated venous or arterial resection were associated with CR-POPF but not All-POPF.

CONCLUSION

In conclusion this study demonstrates wide variation in reported rates of POPF and that several risk factors associated with CR-POPF are not used within risk prediction models. Data from this study can be used to shape future studies, research and audit across ethnic and geographic boundaries in POPF following pancreatoduodenectomy.

The location of perianastomotic fluid collection predicts postoperative complications after pancreaticoduodenectomy

PURPOSE

Perianastomotic fluid collection (PFC) is one of the postoperative complications of pancreaticoduodenectomy (PD). However, no studies have investigated the clinical significance of PFC location and volume during the early postoperative period. This study aimed to assess the association between PFC during the early postoperative period and postoperative complications.

METHODS

Medical records of 148 patients who had undergone PD and computed tomography (CT) on postoperative day 4 were retrospectively reviewed. The location-superior, inferior, ventral, dorsal, or splenic hilum-and PFC index, which is the estimated volume of fluid collection, were determined using CT. The associations between postoperative complication and the presence of PFC, and PFC index according to the location, were assessed.

RESULTS

The PFC group included 102 patients (69%). Postoperative pancreatic fistula (POPF) and organ/space surgical site infection (SSI) were more frequent in the PFC group (42% vs 9%, p < 0.001 and 29% vs 11%, p = 0.020, respectively). Additionally, the PFC index was larger in patients who developed POPF, organ/space SSI, or pseudoaneurysm (81 cm³ vs 19 cm³, p < 0.001; 75 cm³ vs 30 cm³, p = 0.001; and 185 cm³ vs 31 cm³, p < 0.001, respectively). Furthermore, superior and ventral PFCs were associated with pseudoaneurysm (11% vs 0%, p = 0.006 and 14% vs 1%, p = 0.002, respectively), whereas inferior and dorsal PFCs were associated with deep incisional SSI (9% vs 0%, p = 0.027 and 8% vs 1%, p = 0.034, respectively).

CONCLUSION

The PFC location during the early postoperative period is associated with postoperative complications. Our findings may help determine the optimal location of prophylactic drains.

Vimentin Expression in Tumor Microenvironment Predicts Survival in Pancreatic Ductal Adenocarcinoma: Heterogeneity in Fibroblast Population

BACKGROUND

The tumor microenvironment, including cancer-associated fibroblasts (CAFs), plays various clinical roles in cancer growth. CAFs are a heterogeneous population and express a variety of mesenchymal markers. However, the clinical roles for CAFs expressing different markers in pancreatic ductal adenocarcinoma (PDAC) remain unknown.

METHODS

We reviewed 67 resected PDAC patients who had not received preoperative therapy. Each primary tumor was analyzed for vimentin and α-smooth muscle actin (α-SMA) expression by immunohistochemical and dual immunofluorescence staining.

RESULTS

There was no correlation between the percentage of cells expressing vimentin and α-SMA in the tumor stroma (Pearson's correlation coefficient: r = 0.171). Higher vimentin expression (p = 0.018) was associated with significantly shorter overall survival in PDAC patients. Using dual immunofluorescence staining, vimentin-positive CAFs were divided into two subpopulations: co-expression of α-SMA, and no co-expression of α-SMA. In PDAC, the level of co-expression had no effect on survival using univariate analysis (median survival time, 33.3 months for low co-expression vs. 18.2 months for high co-expression; log-rank, p = 0.143). However, multivariate analysis clarified that CAFs expressing vimentin alone was an independent predictor of poor survival (p = 0.014; hazard ratio, 2.305; 95% confidence interval, 1.181-4.497).

CONCLUSIONS

Vimentin-positive CAFs without co-expression of α-SMA were associated with poor survival in PDAC, and CAFs possessed molecular and functional heterogeneity in this disease.