E0439 - CT-Based Pancreatic Stone Density Evaluation Is a Determinant of the Number of Sessions for ESWL Success in Patients With Chronic Calculous Pancreatitis

Introduction: Extracorporeal shock wave lithotripsy (ESWL) is the first line treatment for pancreatic stones in chronic pancreatitis. The role of assessment of stone density on computer tomography (CT) scan in determining the success of ESWL in renal stones has been well established. However, there is limited data on its utility in patients with chronic pancreatitis. In this study, we are investigating the role of CT-based assessment of pancreatic stone density in the success of ESWL in terms of stone fragmentation.

Methods: We retrospectively evaluated chronic pancreatitis patients with pancreatic stones who underwent ESWL therapy. Besides relevant demographic and clinical data, stone-related CT features including number, location, size, and density in terms of the mean value of CT attenuation and pancreatic duct diameter were noted. Details of ESWL including the number of sessions, power, frequency, and the total number of shocks, adverse events, and fragmentation success defined by the breakdown of calculi to < 3mm in size were also recorded. Data was then analyzed to determine the relationship between stone density and parameters of ESWL that determined successful fragmentation.

Results: Nineteen patients (Mean age 54.7±16.8 years, 63.1% female) underwent ESWL. 11(57.9%) patients had alcoholic etiology and the remaining 8(42.1%) were idiopathic. On CT imaging, single stones were found in 7(36.8%), multiple (≥2) stones in 5(26.4%), and a multifocal pattern of calcification was found in the remaining 7(36.8%). The head was the most common site and the mean stone density was 906.7± 478.9Hounsfield units (HU). 14(73.7%) patients needed one session, 4(21.1%) needed two, and 1(5.3%) patient needed five sessions respectively (Table 1). The density of stones requiring a single session for fragmentation was (median 750.5 HU) considerably lower than those requiring two or more sessions(median 1062.3 HU), however, this was not statistically significant (p = 0.74) (Figure 1). 1 patient developed post-procedure pancreatitis.

Discussion: The pancreatic stone density measured using CT is a possible predictor of the technical efficacy of ESWL in terms of the number of sessions required for successful fragmentation.