Ultrasound of the Week: Abdominal Pain
Author: Amel Pineda and Cary Huang
Edited by Christopher Parker, DO and Molly Hartrich, MD
Blog post by Ilyas Taraki
21-year-old female with abdominal pain
21-year-old female with a history of asthma and prior gallstones who presented to the emergency department for worsening intermittent abdominal pain. She was diagnosed with cholelithiasis during her first pregnancy 1 year ago but was lost to surgical follow-up. Her current abdominal pain is similar but with worsening episodes over the last month associated with non-bloody emesis. The pain is described as cramping and exacerbated by eating. She also endorses 2 weeks of diarrhea. Exam is notable for diffuse abdominal tenderness to palpation with no rebound and negative Murphy’s sign. Labs were notable for ALT 104 and AST 63. WBC, bilirubin, and alkaline phosphatase were within normal limits. A point- of- care ultrasound was done. What do you see in the following images?
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This study shows multiple calculi in the gallbladder, with no wall thickening, pericholecystic fluid, or common bile duct dilation. There are also sonographic findings correlating to focal fatty sparing seen with hepatosteatosis (Figure 1). These include:
Increased echogenicity. [1,2]
Focal areas of hypoechoic parenchyma sparing around gallbladder and portal vein. Some sources state these tend to be perivascular in general. [1]
Irregularly shaped morphology, hypoechogenicity in liver segments IV, V, and II. [3,4]
Figure 1. Biliary ultrasound showing cholelithiasis (arrow) with focal fatty sparing (arrowhead). Irregularity of hypoechoic parenchyma surrounding the gallbladder with increased echogenicity of liver (star) supports hepatosteatosis with sparing around the gallbladder.
These findings can often be mistaken for infiltrative or nodular lesions, and hypoechoic regions may also appear like pericholecystic fluid [1].
Focal fatty sparing is a common benign lesion, with one study reporting a prevalence of 6.3% among all patients undergoing ultrasound of the liver [3].
Ultrasound is accurate in identifying fatty liver disease [5]. Ultrasound findings can also be useful for distinguishing focal fatty sparing from liver malignancies. One study reported a sensitivity of 94.38% and specificity of 90.44% [4].
The radiology report confirmed hepatosteatosis and focal fatty sparing without evidence of cholecystitis. The patient was discharged for outpatient follow-up with PCP and surgery.
References
Décarie PO, Lepanto L, Billiard JS, et al. Fatty liver deposition and sparing: A pictorial review. Insights Imaging. 2011;2(5):533-538. doi:10.1007/s13244-011-0112-5.
Walas MK, Skoczylas K, Gierbliński I. Errors and mistakes in the ultrasound diagnostics of the liver, gallbladder and bile ducts. J Ultrason. 2012;12(51):446-462. doi:10.15557/JoU.2012.0032.
Kaltenbach TE, Engler P, Kratzer W, et al. Prevalence of benign focal liver lesions: Ultrasound investigation of 45,319 hospital patients. Abdom Radiol (NY). 2016;41(1):25-32. doi:10.1007/s00261-015-0605-7.
Wu S, Tu R, Liu G, Li H, Zhao Y. Characteristics suggestive of focal fatty sparing from liver malignancy on ultrasound in liver screening. Ultrasound Q. 2014;30(4):276-281. doi:10.1097/RUQ.0000000000000050.
Ballestri S, Nascimbeni F, Baldelli E, et al. Ultrasonographic fatty liver indicator detects mild steatosis and correlates with metabolic/histological parameters in various liver diseases. Metabolism. 2017;72:57-65. doi:10.1016/j.metabol.2017.04.003.