Qualification for endoscopic retrograde cholangiopancreatography in the diagnosis and treatment of extrahepatic cholestasis caused by choledocholithiasis

Use of diffusion-weighted imaging in the noninvasive diagnostic of obstructed biliary ducts

OBJECTIVE

This study sought to evaluate the role of diffusion-weighted imaging (DWI) in differentiation between obstructed and unobstructed bile ducts in patients undergoing magnetic resonance imaging (MRI).

METHODS

Eighty-four patients, 40 males and 44 females (mean age: 56.4 ± 15.1 years), undergoing MRI with DWI (0-50-500-700) were evaluated and divided into two groups: 58 with abnormal laboratory tests (obstructed group) and 26 with normal laboratory values (unobstructed group). Laboratory tests were total bilirubin, alkaline phosphatase, and gamma-glutamyltransferase. Median ADC values were calculated and correlated with laboratory tests and degree of bile-duct dilatation (absent, moderate, or severe). The persistence of signal on DWI (b500 and b700) in the biliary tract was evaluated. Bilirubin values were tested for correlation with bile-duct ADC values and persistence of b700 signal. For statistical analysis, Student t test, chi-square test and Wilcoxon-Mann-Whitney test were used. ADC maps were plotted for three levels of the biliary tree, and a receiver operating characteristic (ROC) curve was calculated.

RESULTS

In the obstructed group, 15 patients had severe dilatation, 24 had moderate dilatation, and 19 had no appreciable dilatation; 38 patients had persistent signal on b700 images. In the unobstructed group, 23 patients had no dilatation and 3 had moderate dilatation; 4 patients had persistent signal on b700 images. Correlation was found between degree of bile-duct dilatation, bilirubin levels, persistence of b700 signal, and ADC map values. The calculated ADC map cutoff value (353 10^-6 mm²/s) was able to differentiate the obstructed and unobstructed groups with 92.3% sensitivity, 81% specificity, and 91.9% accuracy.

CONCLUSIONS

DWI is able to distinguish patients with obstructed versus unobstructed bile ducts, regardless of the degree of dilatation, correlating with clinical and laboratory findings.

The use of different pathology classification systems in preoperative imaging of Mirizzi syndrome

INTRODUCTION

The aim was to evaluate the diagnostic value of the Nakagawa and Csendes pathology classification systems in preoperative imaging of Mirizzi syndrome. Mirizzi syndrome is a type of biliary system obstruction caused by stones impacted in a gallbladder neck or cystic duct situated parallel to the common bile duct, causing extrinsic common bile duct stenosis or obstruction, which can lead to recurrent obstructive jaundice, bile duct erosion, and cholangitis. Therefore, the preoperative identification and classification of Mirizzi syndrome is vital for a good surgical result. We explored the applicability of two pathological classification systems to diagnostic imaging.

MATERIAL AND METHODS

We performed a retrospective analysis of the clinical, computed tomography, and magnetic resonance imaging data of 76 cases of pathologically confirmed Mirizzi syndrome, comparing the applicability of the Csendes and Nakagawa pathology classification systems to preoperative imaging.

RESULTS

The Nagakawa pathology classification system had higher sensitivity, specificity, accuracy, positive predictive value, and positive likelihood ratio, along with lower rates of both missed diagnosis and misdiagnosis. Its positive predictive value and positive likelihood ratios were significantly superior. Adapting the Nagakawa pathological classification system to preoperative imaging produced more consistent results than the Csendes system.

CONCLUSIONS

Compared with the Csendes pathology classification system, the Nagakawa classification is more adaptable to preoperative imaging and treatment planning.