Accuracy and timeliness of an abbreviated emergency department MRCP protocol for choledocholithiasis

Preoperative MRCP Can Rule Out Choledocholithiasis in Acute Cholecystitis with a High Negative Predictive Value: Prospective Cohort Study with Intraoperative Cholangiography

BACKGROUND

Magnetic resonance cholangiopancreatography (MRCP) provides a noninvasive and fast modality for imaging the biliary tree when choledocholithiasis is suspected. Guidelines suggest that MRCP is recommended when strong or moderate signs of common bile duct (CBD) stones are present. Well-performed prospective studies are scarce regarding the sensitivity and specificity of preoperative MRCP in patients with acute cholecystitis in comparison with intraoperative cholangiography, ERCP, or choledochoscopy.

METHODS

We performed a prospective, observational population-based feasibility study in Central Finland Hospital Nova between January 2019 and December 2019. We examined the diagnostic performance of preoperative MRCP on consecutive patients with acute cholecystitis scheduled for index admission cholecystectomy. The accuracy of MRCP was verified with IOC, choledochoscopy, or ERCP. The interobserver reliability of the image quality of MRCP and the sensitivity and specificity of choledocholithiasis were observed independently by three experienced radiologists.

RESULTS

A total of 180 consecutive patients diagnosed with acute cholecystitis followed by index admission cholecystectomy were identified. MRCP was performed in 113/180 (62.8%) patients, and complementary perioperative imaging of the bile ducts was performed in 72/113 (63.7%) patients. The incidence of choledocholithiasis was high (29.2%). In acute cholecystitis, the sensitivity (76.2-85.7%) and specificity (84.3-92.2%) of MRCP were equally compared to the literature with unselected patient groups. The best visibility was observed in the common hepatic duct, the inferior CBD, and the central hepatic duct. The interobserver reliability was excellent for determining the size and quantity of CBD stones.

CONCLUSION

In acute cholecystitis, MRCP yields high negative predictive value regarding detection of choledocholithiasis. If CBD stones were discovered, the interobserver reliability was excellent when measuring the size and number of CBD stones. The best-visualized area was the distal part of the biliary tract, which provides good preoperative workup if choledocholithiasis is present.

Bile duct penetrating duodenal wall sign: a novel computed tomography finding of common bile duct stone impaction into duodenal major papilla

PURPOSE

Impacted common bile duct stones cause severe acute cholangitis. However, the early and accurate diagnosis, especially iso-attenuating stone impaction, is still challenging. Therefore, we proposed and validated the bile duct penetrating duodenal wall sign (BPDS), which shows the common bile duct penetrating the duodenal wall on coronal reformatted computed tomography (CT), as a novel sign of stone impaction.

METHODS

Patients who underwent urgent endoscopic retrograde cholangiopancreatography (ERCP) for acute cholangitis due to common bile duct stones were retrospectively enrolled. Stone impaction was defined by endoscopic findings as a reference standard. Two abdominal radiologists blinded to clinical information interpreted CT images to record the presence of the BPDS. The diagnostic accuracy of the BPDS to diagnose stone impaction was analyzed. Clinical data related to the severity of acute cholangitis were compared between patients with and without the BPDS.

RESULTS

A total of 40 patients (mean age 70.6 years; 18 female) were enrolled. The BPDS was observed in 15 patients. Stone impaction occurred in 13/40 (32.5%) cases. Overall accuracy, sensitivity, and specificity were 34/40 (85.0%), 11/13 (84.6%), and 23/27 (85.2%), respectively; 14/16 (87.5%), 5/6 (83.3%), and 9/10 (90.0%) for iso-attenuating stones; and 20/24 (83.3%), 6/7 (85.7%), and 14/17 (82.4%) for high-attenuating stones. Interobserver agreement of the BPDS was substantial (κ = 0.68). In addition, the BPDS was significantly correlated with the number of factors in the systemic inflammatory response syndrome (P = 0.03) and total bilirubin (P = 0.04).

CONCLUSION

The BPDS was a unique CT imaging finding to identify common bile duct stone impaction regardless of stone attenuation with high accuracy.

Imaging of benign gallbladder and biliary pathologies in pregnancy

The rising incidence combined with pregnancy-related physiological changes make gallbladder and biliary pathology high on the differential for pregnant patients presenting with right upper abdominal pain. Imaging plays a crucial role in determining surgical versus non-surgical management in pregnant patients with biliary or gallbladder pathology. Ultrasound (first-line) and magnetic resonance with magnetic resonance cholangiopancreatography (second-line) are the imaging techniques of choice in pregnant patients with suspected biliary pathology due to their lack of ionizing radiation. MRI/MRCP offers an excellent non-invasive imaging option, providing detailed anatomical detail without known harmful fetal side effects. This article reviews physiological changes in pregnancy that lead to gallstone and biliary pathology, key imaging findings on US and MRI/MRCP, and management pathways.

Use of MR in Pancreaticobiliary Emergencies

This article presents the MR protocols, imaging features, diagnostic criteria, and complications of commonly encountered emergencies in pancreaticobiliary imaging, which include pancreatic trauma, bile leak, acute cholecystitis, biliary obstruction, and pancreatitis. Various classifications and complications that can arise with these conditions, as well as artifacts that may mimic pathology, are also included. Finally, the emerging utility of abbreviated MR protocols is discussed.

ACCURACY OF ABBREVIATED PROTOCOL OF MAGNETIC RESONANCE CHOLANGIO-PANCREATOGRAPHY IN THE DIAGNOSIS OF CHOLEDOCHOLITHIASIS

BACKGROUND

Abbreviated magnetic resonance imaging protocols have emerged to reduce the examination time of the long protocols eliminating unnecessary pulse sequences to answer a targeted clinical question, without compromising diagnostic information.

OBJECTIVE

The objective of this study was to evaluate the diagnostic accuracy of an abbreviated magnetic resonance cholangiopancreatography (A-MRCP) protocol in patients with suspected choledocholithiasis.

METHODS

This retrospective study evaluated patients (ages 10 + years) that performed consecutive MRCP examination from October 2019 to June 2020, with the clinical suspicion of choledocholithiasis. Readers first evaluated the biliary tree using a four-sequence A-MRCP protocol and later reviewed the entire conventional eleven-sequence MRCP. Presence of choledocholithiasis, stone size, common bile duct caliber, and additional findings were evaluated.

RESULTS

A total of 148 patients with MRCP were included (62.8% female, mean 50.9 years). The prevalence of choledocholithiasis was 32.2%. The accuracy of the abbreviated MRCP protocol for choledocholithiasis was 98.7%. There was no difference between the performance of the abbreviated and conventional MRCP image sets for detection of choledocholithiasis (kappa=0.970), with a sensitivity of 98% and a specificity of 99%. There was excellent inter-reader agreement evaluating for choledocholithiasis on both imaging sets of MRCP protocols (kappa values were 0.970).

CONCLUSION

An abbreviated MRCP protocol to evaluate for choledocholithiasis provides similar diagnostic over the conventional MRCP protocol, offering potential for decreased scanning time and improved patient tolerability.

Advances in MR Imaging of the Biliary Tract

Imaging of the biliary system has improved and has allowed MR to become a key noninvasive tool for evaluation of the biliary system. A variety of magnetic resonance cholangiopancreatography techniques have been developed, with improved visualization of the biliary system and biliary pathology. Key avenues of advancement include increasing the speed of acquisition, improving spatial resolution, and reducing artifacts. T1-weighted imaging using gadolinium-based hepatobiliary contrast agents allows for evaluation in additional indications, such as liver donor evaluation, biliary leak identification, and choledochal cyst confirmation. There is potential for further increased utility of MR in the evaluation of the biliary system.