Dynamic assessment of peripancreatic collections in necrotizing pancreatitis using CT and MRI: a retrospective study

Introduction: Acute destructive pancreatitis is associated with high mortality rates. Although contrast-enhanced CT remains the gold standard for initial diagnosis, uncertainties persist regarding the timing and choice of drainage techniques for necrotic collections (ANC), and the impact of their structural characteristics on treatment outcomes is insufficiently studied. This retrospective study aims to comprehensively evaluate the capabilities of CT and MRI in the dynamic assessment of necrotic collections to optimize treatment strategy.

Objective: Comparative analysis of CT and MRI capabilities in characterizing peripancreatic collections during different phases of necrotizing pancreatitis, assessment of the influence of necrotic debris on treatment strategy selection, and evaluation of treatment efficacy.

Materials and Methods: A retrospective analysis of 150 patients (2023–2024) with necrotizing pancreatitis treated at the S. P. Botkin Moscow Clinical Research Center was conducted. Contrast-enhanced CT was performed at admission or within 3 days of disease onset, then every 7–10 days and preoperatively; MRI was performed when indicated. Each imaging study assessed the size of largest collections, presence of solid components, and communication with the pancreatic ductal system. Statistics: For comparison of quantitative data, Student’s t-test was used (data are presented as mean ± standard deviation). Categorical variables were analyzed using the chi-square test (presented as absolute numbers and percentages). The diagnostic value of the methods (CT and MRI) was assessed by calculating sensitivity and specificity. Statistical significance was set at p<0.05. RESULTS: Peak sizes of peripancreatic collections were observed on days 7–9 after disease onset. Increased collection sizes after 2 weeks correlated with pancreatic duct injury signs on CT/MRI. Collections without debris showed rapid volume expansion in phase 1A followed by gradual resolution after 2–3 weeks, while debris-containing collections developed more slowly and maintained their volume longer. Debris presence correlated with higher disease severity and mortality but not with collection location. Surgical intervention significantly reduced collection sizes in most cases, except for percutaneous catheter drainage which showed markedly reduced efficacy when debris was present. DISCUSSION: Comprehensive imaging plays a key role in the assessment of peripancreatic collections in destructive pancreatitis. Although CT remains the gold standard for initial diagnosis, MRI offers advantages in tissue differentiation and evaluation of collection structure at later stages. Structural features of collections, such as the presence of sequestra and communication with the ductal system, are of great importance for prognosis and treatment strategy selection. The presence of sequestra is associated with risks of prolonged persistence, infection, and ineffective percutaneous drainage. The combined use of CT and MRI allows for optimization of intervention timing, prediction of drainage effectiveness, and avoidance of unnecessary procedures, which ultimately may improve treatment outcomes. CONCLUSIONS: CT accurately tracks peripancreatic collection dynamics, enabling objective disease monitoring. Late-phase MRI demonstrates superior sensitivity (89%) for detecting debris compared to CT (63%). MRI also shows higher sensitivity than CT (92% vs 21%) in identifying pancreatic duct communications. Combined use of both modalities optimizes surgical decision-making. КЛЮЧЕВЫЕ СЛОВА: computed tomography, magnetic resonance imaging, necrotizing pancreatitis, necrotic debris, pancreatic duct communicatio> < 0.05.

Results: Peak sizes of peripancreatic collections were observed on days 7–9 after disease onset. Increased collection sizes after 2 weeks correlated with pancreatic duct injury signs on CT/MRI. Collections without debris showed rapid volume expansion in phase 1A followed by gradual resolution after 2–3 weeks, while debris-containing collections developed more slowly and maintained their volume longer. Debris presence correlated with higher disease severity and mortality but not with collection location. Surgical intervention significantly reduced collection sizes in most cases, except for percutaneous catheter drainage which showed markedly reduced efficacy when debris was present.

Discussion: Comprehensive imaging plays a key role in the assessment of peripancreatic collections in destructive pancreatitis. Although CT remains the gold standard for initial diagnosis, MRI offers advantages in tissue differentiation and evaluation of collection structure at later stages. Structural features of collections, such as the presence of sequestra and communication with the ductal system, are of great importance for prognosis and treatment strategy selection. The presence of sequestra is associated with risks of prolonged persistence, infection, and ineffective percutaneous drainage. The combined use of CT and MRI allows for optimization of intervention timing, prediction of drainage effectiveness, and avoidance of unnecessary procedures, which ultimately may improve treatment outcomes.

Conclusion: CT accurately tracks peripancreatic collection dynamics, enabling objective disease monitoring. Late-phase MRI demonstrates superior sensitivity (89%) for detecting debris compared to CT (63%). MRI also shows higher sensitivity than CT (92% vs 21%) in identifying pancreatic duct communications. Combined use of both modalities optimizes surgical decision-making.

1. Banks P.A., Bollen T.L., Dervenis C. et al. Acute Pancreatitis Classification Working Group. Classification of acute pancreatitis-2012: revision of the Atlanta classification and definitions by international consensus // Gut. 2013. Vol. 62, No. 1. Р. 102–111. doi: 10.1136/gutjnl-2012-302779.

2. Rocha A.P.C., Schawkat K., Mortele K.J. Imaging guidelines for acute pancreatitis: when and when not to image // Abdom. Radiol. (NY). 2020. Vol. 45, No. 5. Р. 1338–1349. doi: 10.1007/s00261-019-02319-2.

3. Petrov M.S., Yadav D. Global epidemiology and holistic prevention of pancreatitis // Nat. Rev. Gastroenterol. Hepatol. 2019. Vol. 16, No. 3. Р. 175–184. doi: 10.1038/s41575-018-0087-5.

4. Heckler M., Hackert T., Hu K. et al. Severe acute pancreatitis: surgical indications and treatment // Langenbecks Arch. Surg. 2021. Vol. 406, No. 3. Р. 521–535. doi: 10.1007/s00423-020-01944-6.

5. Meyrignac O., Lagarde S., Bournet B. et al. Acute pancreatitis: extrapancreatic necrosis volume as early predictor of severity // Radiology. 2015. Vol. 276, No. 1. Р. 119–128. doi: 10.1148/radiol.15141494.

6. Mikó A., Vigh É., Mátrai P. et al. Computed Tomography Severity Index vs. Other Indices in the Prediction of Severity and Mortality in Acute Pancreatitis // Front Physiol. 2019. Vol. 10. Р. 1002. doi: 10.3389/fphys.2019.01002.

7. Dyuzheva T.G., Shefer A.V., Dzhus E.V. et al. Diagnosis of pancreatic duct disruption in acute pancreatitis. Annals of HPB Surgery, 2021, Vol. 26, No. 2, pp. 15–24 (In Russ.).

8. Vanek P., Urban O., Trikudanathan G., Freeman M.L. Disconnected pancreatic duct syndrome in patients with necrotizing pancreatitis // Surg. Open Sci. 2022. Vol. 11. Р. 19–25. doi: 10.1016/j.sopen.2022.10.009.

9. Takenaka M., Saito T., Hamada T. et al. Disconnected pancreatic duct syndrome: diagnostic and therapeutic challenges // Expert Rev. Gastroenterol Hepatol. 2024. Vol. 18, No. 10. Р. 631–645. doi: 10.1080/17474124.2024.2419056.

10. Maatman T.K., Roch A.M., Ceppa E.P. et al. The continuum of complications in survivors of necrotizing pancreatitis // Surgery. 2020. Vol. 168, No. 6. Р. 1032– 1040. doi: 10.1016/j.surg.2020.07.004.

11. Baron T.H., DiMaio C.J., Wang A.Y., Morgan K.A. American Gastroenterological Association Clinical Practice Update: Management of Pancreatic Necrosis // Gastroenterology. 2020. Vol. 158, No. 1. Р. 67–75. doi: 10.1053/j.gastro.2019.07.064.

12. Arablinskii A.V., Titov M.Y., Buslavskaya A. CT and MRI in the diagnosis of the phase course of necrotizing pancreatitis // REJR. 2022. Vol. 12, No. 3, pp. 58–73 (In Russ.). doi: 10.21569/2222-7415-2022-12-3-58-73.

13. Shabunin A.V., Lukin A.Yu., Shikov D.V. Optimal treatment of acute pancreatitis. Annals of HPB Surgery, 2013, Vol. 18, No. 3, pp. 70–78 (In Russ.).

14. Shabunin A.V., Bedin V.V., Lukin A.Yu. et al. Experience with minimally invasive necrosectomy techniques. Moscow Surgical Journal. 2021. Special Issue. Р. 53 (In Russ.).

15. Rashid M.U., Hussain I., Jehanzeb S. et al. Pancreatic necrosis: Complications and changing trend of treatment // World J. Gastrointest. Surg. 2019. Vol. 11, No. 4, pp. 198–217. doi: 10.4240/wjgs.v11.i4.198.

16. Choudhury S.R., Manoj M., Gupta P. et al. Wall maturation in necrotic collections in acute pancreatitis // Acta Gastroenterol. Belg. 2022. Vol. 85, No. 3, pp. 463– 467. doi: 10.51821/85.3.9701.

17. Bhatia H., Johnson J. et al. Tracking Wall Characteristics of Necrotic Pancreatic Fluid Collections // Indian J. Radiol. Imaging. 2024. Vol. 34, No. 4. Р. 620–627. doi: 10.1055/s-0044-1785683.

18. Koo J.G., Liau M.Y.Q., Kryvoruchko I.A. et al. Pancreatic pseudocyst: The past, the present, and the future // World J. Gastrointest. Surg. 2024. Vol. 16, No. 7. Р. 1986–2002. doi: 10.4240/wjgs.v16.i7.1986.

19. Arablinskii A.V., Buslavskaya A., Pichugina N.V., Titov M.Yu. Combination of ductal adenocarcinoma and postnecrotic pseudocyst. REJR, 2023, Vol. 13, No. 2, рр. 147–154 (In Russ.). doi: 10.21569/2222-7415-2023-13-2-147-154.

20. Cherdantsev D.V., Pervova O.V., Noskov I.G. et al. Possibility of radiology diagnostics of pancreatic pseudocysts. REJR, 2018, Vol. 8, No. 4, pp. 111–117 (In Russ.). doi: 10.21569/2222-7415-2018-8-4-111-117.

21. Rana S.S., Sharma R.K., Gupta P., Gupta R. Natural course of asymptomatic walled off pancreatic necrosis // Dig. Liver. Dis. 2019. Vol. 51, No. 5. Р. 730–734. doi: 10.1016/j.dld.2018.10.010.

22. Easler J., Papachristou G.I. The morphologic evolution of necrotic pancreatic fluid collections // Ann. Gastroenterol. 2014. Vol. 27, No. 3. Р. 191–192.

23. Theerasuwipakorn N., Tasneem A.A., Kongkam P. et al. Walled-off Peripancreatic Fluid Collections in Asian Population // J. Transl. Int. Med. 2019. Vol. 7, No. 4. Р. 170–177. doi: 10.2478/jtim-2019-0032.

24. Kumar M., Sonika U., Sachdeva S. et al. Natural History of Asymptomatic Walled-off Necrosis // Cureus. 2023. Vol. 15, No. 2, p. e34646. doi: 10.7759/cureus.34646.

25. Liu Z., Liu P., Xu X. et al. Timing of minimally invasive step-up intervention for symptomatic pancreatic necrotic fluid collections // Clin. Res. Hepatol. Gastroenterol. 2023. Vol. 47, No. 4. Р. 102105. doi: 10.1016/j.clinre.2023.102105.