Monitoring Fibrosis of the Pancreatic Remnant After a Pancreaticoduodenectomy With Dynamic MRI

Pancreatic fibrosis assessment and association with pancreatic cancer: comparison with the extracellular volume fraction

AIMS

To compare the iodine washout rate (IWR) from multiphasic contrast-enhanced computed tomography (CT) with the extracellular volume fraction (fECV) for assessing pancreatic fibrosis and its association with pancreatic cancer.

MATERIALS AND METHODS

The study included 51 individuals (33 men; median age: 69 years; 21 with pancreatic cancer, 30 with other diseases) who underwent multiphasic contrast-enhanced CT and histological evaluation for fibrotic changes in pancreas. The histological pancreatic fibrosis fraction (HPFF) was assessed on Azan-stained sections. Pancreatic parenchymal enhancement values were measured to calculate IWR and fECV. Statistical methods, such as Spearman's rho and Mann-Whitney U-test, were used. Linear regression models using IWR and fECV were constructed to predict HPFF, with the performance expressed as root mean squared error (RMSE) and Akaike information criterion (AIC).

RESULTS

HPFF correlated with all CT parameters at the estimated transection line, strongest for IWRPPP-EP (r=-0.69, P<0.01). HPFF and fECV values were higher in the pancreatic cancer group than in controls (30% vs. 12.5%, P<0.01; 40.3% vs. 33.0%, P<0.01), whereas IWR values were lower (IWRPPP-EP: 43.3% vs. 55.0%, P<0.01; IWRPVP-EP: 25.0% vs. 33.5%, P<0.01). Linear regression models combining IWRPPP-EP + fECV and IWRPVP-EP + fECV were superior for predicting HPFF, with lower RMSE (9.23-9.35) and AIC (379.38-380.72) values than models with IWR or fECV alone.

CONCLUSION

IWRPPP-EP, IWRPVP-EP, and fECV were reliable biomarkers for noninvasively assessing pancreatic fibrosis and were associated with pancreatic cancer risk. Linear regression combining these variables showed enhanced predictive accuracy for pancreatic fibrosis.

Use of gadoxetic acid-enhanced MRI to predict the development of postoperative pancreatic fistulas by estimating the degree of pancreatic fibrosis

BACKGROUND

Postoperative pancreatic fistula (POPF) can be life-threatening, and gadoxetic acid-enhanced MRI is routinely performed in patients undergoing pancreatic surgery. However, previous reports have not investigated if gadoxetic acid-enhanced MRI can be used to predict POPF risk.

OBJECTIVE

This study aims to explore if gadoxetic acid-enhanced MRI can predict pancreatic fibrosis and the need for POPF treatment before surgery.

METHOD

We retrospectively analyzed gadoxetic acid-enhanced MR images from 142 patients who underwent pancreatic surgery between January 1, 2011, and April 30, 2018. Pre-dynamic signal intensity (SI) and values for portal, transitional, and hepatobiliary phase standardized based on pre-dynamic study values were analyzed. The diameter of the main pancreatic duct (DMPD) was measured, and the degree of pancreatic fibrosis was classified as F0-F3. We defined POPF higher than grade B as significant.

RESULTS

Odds ratios for combinations that led to any degree of fibrosis higher than grade B were defined as significant risk factors. The highest odds ratio was obtained for F0 vs. F1-F3 (p = 0.038). DMPD (p < 0.001), pre-SI (p = 0.008), portal-SI/pre-SI (p < 0.001), transitional-SI/pre-SI (p < 0.001), and hepatobiliary-SI/pre-SI (p = 0.012) were significantly correlated with the presence of fibrosis. The presence of fibrosis was best detected by DMPD (AUC = 0.777). Individual specificity values of transitional-SI/pre-SI and DMPD were 95.5% and 86.6%, respectively, and their combined specificity was 97.7%.

CONCLUSION

The absence of pancreatic fibrosis is a risk factor for developing POPF higher than grade B. DMPD was the most useful diagnostic indicator of the presence of fibrosis among our analysis, and its specificity increased when combined with transitional-SI/pre-SI.

Role of ultrasound shear wave elastography in preoperative prediction of pancreatic fistula after pancreaticoduodenectomy

BACKGROUND

Majority of predictors of postoperative pancreatic fistula (POPF) use intraoperative variables. We aimed to study the role of preoperative ultrasound shear wave elastography (USWE) to predict POPF.

METHODS

The consecutive patients who underwent pancreaticoduodenectomy (PD) between January 2019 to March 2020 were prospectively enrolled. All patients underwent USWE assessment at the pancreatic neck level. Intraoperative variables including pancreatic texture, pancreatic duct diameter, blood loss and histological grading of fibrosis were also recorded. Associations between USWE and intraoperative variables and histological grading with the development of POPF were analyzed.

RESULTS

Of the 62 patients assessed, 50 patients (mean age: 53 ± 14 years; 31 males) were included. POPF and clinically relevant POPF (CRPOPF) were observed in 22 (44%) and 7 (14%) patients respectively. Soft pancreas was an independent predictor of CRPOPF (p = 0.04). The mean USWE valve was significantly lower in patients with CRPOPF as compared to no CRPOPF (9.7 Kpa vs. 12.8Kpa, p = 0.016). At receiver operating characteristic curve analysis, USWE value of 12.65Kpa yielded sensitivity and specificity of 100% and 47%, respectively, for prediction of CRPOPF. USWE showed significant correlation with intraoperative pancreatic texture (Spearman's rank correlation coefficient (ρ) = 0.565, p = 0.001).

CONCLUSION

USWE helps in preoperative prediction of CRPOPF. This may further help to customize management strategy in high risk patients.

Preoperative imaging evaluation of pancreatic pathologies for the objective prediction of pancreatic fistula after pancreaticoduodenectomy

In performing pancreaticoduodenectomy (PD) or when conducting clinical trials involving PD procedure, a universal platform for predicting the risk of postoperative pancreatic fistula (POPF) is indispensable. In this article, the most significant imaging studies that focused on the objective preoperative assessment of pancreatic pathologies in association with the occurrence of POPF after PD were reviewed. Several recently developed imaging modalities can objectively predict the occurrence of POPF after PD by assessing the elasticity, fibrosis, and fatty infiltration of the pancreas. These valuable imaging modalities include: (1) acoustic radiation force impulse ultrasound (US) electrography which provides information about the elastic properties of the pancreas; (2) contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) with/without contrast-enhancement which reflect the histological degree of pancreatic fibrosis; and (3) multi-detector row CT and/or MRI which reflects the microscopic fatty infiltration of the pancreas. The precise and objective preoperative risk assessment of POPF enables surgeons to customize appropriate management strategies for individual patients undergoing PD. This would be also beneficial for stratifying patients for enrolment in relevant studies that involve pancreatic head resection, as objective criteria could be set for the definitive evaluation of collected data related to surgical outcomes across different institutions and surgeons.

Predict pancreatic fistula after pancreaticoduodenectomy: ratio body thickness/main duct

BACKGROUND

The occurrence of post-operative pancreatic fistula (POPF) after pancreaticoduodenectomy is a challenging issue. The aim was to identify variables on preoperative computed tomography (CT) scan, useful to predict clinically significant POPF (grades B-C) after pancreaticoduodenectomy.

METHODS

Patients presented POPF after pancreaticoduodenectomy were included from two tertiary referral centres. B/W ratio was defined by ratio of pancreas body thickness (B) to main pancreatic duct (W). The predictive parameters of POPF on CT scan were assessed with a receiving operator characteristics (ROC) curve and intrinsic characteristics.

RESULTS

Between 2010 and 2013, 186 patients who underwent pancreaticoduodenectomy were included. POPF occurred in 25% of them, and was clinically significant in 13%. After univariate analysis, endocrine tumours (P = 0.03), main pancreatic duct size (P < 0.01) and B/W ratio (P = 0.04) were significantly associated with POPF. ROC curve showed a greater area under curve for B/W ratio (0.68) than for main pancreatic duct size (0.33). A 3.8 threshold displayed 80 and 51% for sensibility and specificity, respectively, and a negative predictive value of 94%. A B/W ratio >3.8 increased the rates of post-operative haemorrhage (odds ratio = 4.3 (1.4-13.2), P = 0.01), and reintervention (odds ratio = 3.4 (1.2-9.6), P = 0.02).

CONCLUSIONS

B/W ratio superior to 3.8 assessed on preoperative CT scan may be an easy tool to predict clinically significant POPF after pancreaticoduodenectomy.

Prediction of postoperative pancreatic fistulas after pancreatectomy: assessment with acoustic radiation force impulse elastography

OBJECTIVES

The purpose of this prospective study was to investigate the usefulness of acoustic radiation force impulse (ARFI) elastography of the pancreas for predicting postoperative pancreatic fistula occurrence after pancreatic resection.

METHODS

Twenty-five patients underwent ARFI elastography of the pancreas before pancreatic resection (11 men and 14 women; mean age, 59.1 years; range, 28-76 years). In each patient, 3 valid ARFI measurements (meters per second) were performed at the head of the pancreas, and the median values were calculated. Patients underwent pancreaticoduodenectomy (n = 18) or distal pancreatectomy (n = 7). Clinically relevant fistulas (grade B or higher) were determined according to the standard criteria used by the International Study Group on Pancreatic Fistula. Preoperative ARFI values were compared between the fistula and nonfistula groups (Mann-Whitney test).

RESULTS

Clinically relevant fistulas (grade B or higher) were observed in 8 patients (32%; fistula group), including 5 of 18 patients with pancreaticoduodenectomy (28%) and 3 of 7 patients with distal pancreatectomy (43%). The ARFI values in the fistula group (median, 1.45 m/s; range, 0.80-1.98 m/s) were lower than in the nonfistula group (median, 1.54 m/s; range, 0.98-3.40 m/s), but there was no statistical significance (P = .1374). When confining the results to only patients with pancreaticoduodenectomy, the ARFI values were significantly lower in the patients with fistulas (median, 0.98 m/s; range, 0.80-1.94 m/s) than in those without fistulas (median, 1.60 m/s; range, 1.08-3.40 m/s; P = .0460).

CONCLUSIONS

This preliminary study showed the potential feasibility of a clinical application of ARFI elastography in preoperatively predicting postoperative pancreatic fistulas after pancreaticoduodenectomy. Investigation of this method in larger studies is needed.

Pancreaticojejuno anastomosis after pancreaticoduodenectomy: brief pathophysiological considerations for a rational surgical choice

Introduction. The best pancreatic anastomosis technique after pancreaticoduodenectomy (PD) is still debated. Pancreatic fistula (PF) is the most important complication but is also related to postoperative bleedings and pancreatic remnant involution. We support pancreaticojejuno anastomosis (PJ) advantages describing our technique with brief technical considerations. Materials and Methods. 89 consecutive patients underwent PD with suprapyloric gastric resection and double loop reconstruction. Pancreaticojejunal end-to-end anastomosis was done by simple invagination with a single layer of interrupted pledget-supported Ticron stitches. Results. Pancreatic fistula occurred in seven patients (7.8%): six cases of grade A fistula resolved spontaneously, and in only one case of grade B fistula percutaneous drainage was necessary. Postoperative hemorrhage occurred in only two (2.2%) of 89 patients. Conclusion. Pancreaticojejunostomy with minor changes in anastomotic techniques can contribute to improvement of the outcome of Roux-en-Y reconstruction regarding PF and other related complications. The particular reconstruction reported seems also to preserve the pancreatic exocrine function.