Cystic artery velocity as a predictor of acute cholecystitis

Cystic artery velocity as a predictor of acute cholecystitis

WHY THE STUDY WAS PERFORMED

Acute right upper quadrant pain is a common complaint among patients presenting to the emergency department. Numerous clinical and societal guidelines recommend abdominal ultrasound as the first line imaging modality for patients with right upper quadrant pain and suspected biliary disease. Although ultrasound is over 96% accurate in the diagnosis of cholelithiasis, the sensitivity and specificity of ultrasound for acute cholecystitis is variable.

Gallbladder hyperemia has been observed in acute cholecystitis due to increased cystic artery flow. This article hypothesized that the cystic artery peak systolic flow (PSV) may be used as an ultrasound criterion to reflect acute inflammation and hence improve the accuracy of ultrasound in the diagnosis of acute cholecystitis.

HOW THE STUDY WAS PERFORMED

The study was a retrospective analysis of 127 patients (> 18 years of age) who underwent an abdominal ultrasound with an indication specifically to investigate right upper quadrant pain. The data was collected over an eight month period. The electronic medical record (EMR) was reviewed to identify patients who underwent definitive treatment within six days of the ultrasound examination (43 patients). Patients were excluded if they were pregnant, had a history of cirrhosis, hepatocellular cancer, TIPSS or hepatic metastases. To establish a control group, cystic artery PSV (angle corrected with an insonation angle of less than 60 degrees) was collected in 108 outpatients undergoing abdominal ultrasound. Patients with clinical suspicion of acute cholecystitis were excluded. In this control group, the cystic artery PSV was measurable in 30 out of 51 patients.

In summary, out of the 73 sampled cystic arteries: 22 had acute cholecystitis at surgery, 3 had acute cholecystitis based on cholecystostomy tube placement, 18 had chronic cholecystitis, and 30 compromised the control group.

Three radiologists independently assessed all the abdominal scan images and were blinded to the original report and pathological diagnosis. Each study was also evaluated for cholelithiasis, CBD diameter, stone impaction in the GB neck, sludge, GB wall thickness of > 3mm, GB distension of > 4cm in transverse and > 8 cm in length and tensile GB fundus sign (defined as the identification of a bulging gallbladder fundus against the anterior abdominal wall due to the resistance of being flattened by the anterior abdominal wall). Patient white cell count, patient heart rate, age and gender were also recorded.

WHAT THE STUDY FOUND

Of 73 patients, 43 underwent definitive treatment: 40 patients underwent cholecystectomy and 3 had percutaneous cholecystostomy tube placement. Of the 43 patients, 25 had acute cholecystitis and 18 chronic cholecystitis. 30 control patients were examined.

There were no statistically significant differences between the 73 patients in terms of age, tachycardia, fever or mean white cell count.

REVIEWED BY Marilyn Zelesco ASA SIG Abdominal

REFERENCE Perez M, Tse JR, Bird K, Liang T, Brooken Jeffrey R, Kamaya A. Abdominal Radiology 2021; 44:4720 – 4728

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Cystic artery velocity as a predictor of acute cholecystitis continued

Mean cystic artery PSV (CA PSV) was elevated in patients with acute cholecystitis, measuring 50 +/- 16 cm/s, versus 28 +/- 8 cm/s for chronic cholecystitis and 22 +/- 8 cm/s in the control group. There were no statistically significant differences between CA PSV in patients with chronic cholecystitis and the control group.

Mean hepatic artery PSV (HA PSV) was also elevated in patients with acute cholecystitis measuring 121 +/- 61cm/s, versus 86 +/- 45 cm/s in chronic cholecystitis and 71 +/- 24 cm/s in the control group. Similarly, there were no statistically significant differences between HA PSV in patients with chronic cholecystitis and the control group.

In comparison of B-mode features of acute versus chronic cholecystitis, univariate analysis showed that GB wall thickness > 3mm, stone impaction and GB distension of > 8 cm were statistically significant. Other features such as CBD size, cholelithiasis, sludge, sonographic Murphy’s sign, transverse GB distensions > 4cm, pericholecystic fluid, tensile GB fundus sign and pericholecystic echogenic fat were not statistically significant.

RELEVANCE TO CLINICAL PRACTICE

In an evaluation of patients with acute right upper quadrant pain, a cystic artery PSV of > 40 cm/s has a 72% sensitivity, 94% specificity, 95% PPV, 71% NPV and 81% accuracy for differentiating acute from chronic cholecystitis. n