Magnetic Resonance Cholangiopancreatography in the Differential Diagnosis of Biliary Tract Diseases and in the Choice of Surgical Treatment Tactics

The dissertation focuses on the role of magnetic resonance cholangiopancreatography (MRCP) in the differential diagnosis of surgical diseases of the biliary tract and in the selection of surgical treatment tactics. The study aims to improve the MRCP methodology, investigate the causes of false-positive and false-negative diagnostic results, and evaluate the informativeness of MRCP in comparison with intraoperative examination methods. The semiotic features of MRCP are examined across a range of biliary tract conditions, including gallbladder stones, cholesterolosis, gallbladder cancer, choledocholithiasis, inflammatory diseases, benign and malignant strictures, cystic transformation of the ducts, and space-occupying lesions. The work identifies technical artifacts and limitations of the method, proposes ways to address them, and demonstrates that MRCP is comparable in informativeness to intraoperative methods and can serve as a viable alternative. The practical significance lies in the reduction of invasive diagnostic interventions and improved diagnostic outcomes following reconstructive surgery.

Pathological changes of the biliary system requiring surgical correction are characterized by a diversity of forms and a sufficient degree of clinical similarity. At the same time, operative methods of intervention on the bile ducts occupy one of the leading positions in frequency among all operations in abdominal surgery (7, 22, 34, 42, 44).

The widespread adoption over the past decade of new operative methods, such as laparoscopic cholecystectomy, has not reduced but, in some medical institutions, has even increased the frequency of intra- and postoperative complications by 2-4 times, which amounts to 0.1-3% of the total number of surgical interventions (1, 6, 9, 35, 48, 66, 103, 134, 161). One of the reasons for this is the insufficient volume of information obtained before surgery about the structural variants of the biliary tract, as well as about complications of the biliary tract. (12, 13, 23, 25, 39, 41, 147, 182, 192).

To date, the routine method for assessing the state of the bile ducts is standard transcutaneous ultrasonography. Despite a number of advantages of ultrasound — its non-invasiveness and simplicity of application — this method does not have sufficient sensitivity in the evaluation of a number of biliary tract diseases (61, 105, 151, 157). In particular, the sensitivity of this method in diagnosing changes in the distal segments of the biliary tract is only 10-15% (4; 12, 42, 43, 69, 116).

Another widely used non-invasive method of examination of the biliary tract is computed tomography (CT), however, it is most informative in patients with obstruction of the biliary tract. Upon decompression of the biliary tract, its effectiveness is significantly reduced (15, 47, 58, 102, 200).

Decisive significance in the verification of diagnosis is currently preserved by radiological methods of direct contrast enhancement of the bile ducts: endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC), the overall accuracy of which reaches 90-97%, as well as intraoperative diagnostic methods: intraoperative ultrasound (IOUS) and intraoperative cholangiography (IOC) (22, 28, 35, 40).

However, these techniques are associated with a high risk of complications: the total number of complications of endoscopic retrograde cholangiopancreatography and endoscopic papillosphincterotomy can reach 10.6%, of which 7.3% are severe, and mortality from retrograde interventions on the ducts is 0.1-1% (20, 49, 99, 170).

A new method — magnetic resonance cholangiopancreatography (MRCP) — allows non-invasive visualization of the bile and pancreatic ducts in their physiological state, without the use of a contrast agent and without any side effects. At the same time, the capabilities of MRCP, in the opinion of many authors, are comparable to invasive methods of direct contrast enhancement for the most common diseases of the bile ducts, such as choledocholithiasis (4, 89, 115, 140, 192), malignant obstruction of the biliary tract (87, 96), and congenital anomalies (90, 182, 189).

Despite its existing advantages, this method has a number of limitations in the visualization of the bile ducts, which are associated with artifacts caused by the presence of air in the lumen of the bile ducts, artifacts arising from vascular pulsation crossing the duct, and other limitations due to the characteristics of the MRCP method based on signal acquisition from stationary fluid in the lumen of hollow structures (109, 192, 197).

A number of technical and differential criteria of MRCP have been resolved in diagnostic research. At the same time, errors in MRCP that complicate the diagnosis of bile duct diseases, problems of differential diagnosis of various bile duct diseases after reconstructive operations, and questions of differential diagnosis of choledocholithiasis and other conditions of the bile ducts have been reflected in the contemporary literature as unresolved tasks. This circumstance predetermined the relevance of setting the goal and objectives of the study.

Goal of the study:

To determine the role and place of magnetic resonance cholangiopancreatography in the differential diagnosis of surgical diseases of the bile ducts and in the choice of surgical treatment tactics.

Objectives of the study

1. To improve the methodology of magnetic resonance cholangiopancreatography on a 1.0 T magnetic resonance tomograph in the diagnosis of surgical diseases accompanied by changes in the biliary tract.

2. To study the causes of false-positive and false-negative results of MRCP diagnostics of bile duct diseases.

3. To study the diagnostic efficiency of magnetic resonance cholangiopancreatography in complications of cholelithiasis for the choice of further diagnostic and surgical treatment tactics based on a comparative analysis of MRCP results and intraoperative methods of bile duct examination.

4. To establish the diagnostic efficiency and significance of MRCP in differential diagnosis during comprehensive examination of the biliary tract and in the choice of surgical tactics.

Scientific novelty

For the first time in a comparative aspect, the possibilities of modern methods of radiological examination of the biliary tract (intraoperative ultrasound, intraoperative cholangiopancreatography, endoscopic retrograde cholangiopancreatography, magnetic resonance cholangiopancreatography) have been studied, and the diagnostic informativeness of MRCP within the framework of comprehensive magnetic resonance diagnostics of bile duct diseases has been evaluated.

The causes and possible ways to overcome limitations in the visualization of the biliary tree have been identified, both through the selection of special MRCP scanning modes and through additional techniques such as oral contrast enhancement of the duodenum and multi-positional patient examination.

Ways to reduce the frequency of false-positive and false-negative results through additional reconstruction techniques have been identified.

A comparison of MRCP semiotics of various bile duct diseases with semiotics in contrast examination methods has been performed, and features of bile duct change visualization on MRCP have been identified.

It has been established that the MRCP method in terms of informativeness is comparable to intraoperative bile duct examination methods, and in a number of clinical situations, magnetic resonance tomography can serve as an alternative to intraoperative examination methods.

Practical value

The methodology for performing bile duct examinations using magnetic resonance cholangiopancreatography in surgical diseases of the bile ducts has been improved and detailed described.

A detailed analysis of errors and limitations of the method has been provided, along with recommendations for their prevention to improve the effectiveness of diagnostic studies conducted.

MRCP semiotics of various bile duct diseases requiring surgical correction, as well as semiotics of bile duct changes after various reconstructive operations, have been studied and supplemented. By comparing MRCP data with instrumental examination data, surgical intervention results, and morphological examination of biopsy and operative material, the clinical significance of this method in diagnosing various diseases affecting the bile ducts has been determined.

The use of the MRCP method in combination with intraoperative examination methods has significantly reduced the number of invasive diagnostic interventions on the bile ducts, lowered the risk of complications after these interventions, and improved the results of diagnosing bile duct complications after reconstructive operations.

SCOPE AND STRUCTURE OF THE DISSERTATION

The work is presented in 154 pages of typeset text and consists of a list of abbreviations, table of contents, introduction, 6 chapters, conclusion, findings, and practical recommendations. The work includes 15 tables, 3 diagrams, and is illustrated with 65 figures. The bibliography includes 205 sources, of which 51 are by domestic and 154 by foreign authors.

ALL

The author considers it his duty to express sincere gratitude and appreciation to the administration of the Federal State Institution «Institute of Surgery named after A.V. Vishnevsky of Rosmedtechnology» where the work was carried out, and personally to Academician of the Russian Academy of Medical Sciences Vladimir Dmitrievich Fedorov for providing the opportunity to carry out this work. Special gratitude is expressed to the scientific supervisors — the head of the radiology department, Doctor of Medical Sciences, Professor Grigory Grigorievich Karmazanovsky, and Doctor of Medical Sciences Yury Gennadievich Starkov. Deep gratitude is expressed to the senior researchers of the surgical endoscopy department, Kirill Vyacheslavovich Shishin and Elena Nikolaevna Solodina, and the senior researcher of the radiology department, Irina Petrovna Kolganova. It is necessary to thank the engineer of the radiology department, Vladimir Mikhailovich Mosin, for his assistance in the technical processing of illustrative material. Sincere gratitude is expressed to the senior nurse of the radiology department, Nina Pavlovna Metalnikova, and all employees of the radiology department, as well as to the collective of the Institute for constant support and assistance in the work.