Magnetic resonance imaging and diseases of the liver and biliary tract. Part 2. Magnetic resonance cholangiography and angiography and conclusions

Abstract

Magnetic resonance cholangiography (MRC) relies on the strong T2 signal from stationary liquids, in this case bile, to generate images. No contrast agents are required, and the failure rate and risk of serious complications is lower than with endoscopic retrograde cholangiopancreatography (ERCP). Data from MRC can be summated to produce an image much like the cholangiogram obtained by using ERCP. In addition, MRC and conventional MRI can provide information about the biliary and other anatomy above and below a biliary obstruction. This provides information for therapeutic intervention that is probably most useful for hilar and intrahepatic biliary obstruction. Magnetic resonance cholangiography appears to be similar to ERCP with respect to sensitivity and specificity in detecting lesions causing biliary obstruction, and in the diagnosis of choledocholithiasis. It is also suited to the assessment of biliary anatomy (including the assessment of surgical bile‐duct injuries) and intrahepatic biliary pathology. However, ERCP can be therapeutic as well as diagnostic, and MRC should be limited to situations where intervention is unlikely, where intrahepatic or hilar pathology is suspected, to delineate the biliary anatomy prior to other interventions, or after failed or inadequate ERCP. Magnetic resonance angiography (MRA) relies on the properties of flowing liquids to generate images. It is particularly suited to assessment of the hepatic vasculature and appears as good as conventional angiography. It has been shown to be useful in delineating vascular anatomy prior to liver transplantation or insertion of a transjugular intrahepatic portasystemic shunt. Magnetic resonance angiography may also be useful in predicting subsequent variceal haemorrhage in patients with oesophageal varices.

Role of Magnetic Resonance Cholangiopancreatography in Biliary Disorders

“…Static or slow moving fluid filled structures such as bile duct appears hyper intense areas, whereas background tissues some signal. This inherent difference in signal intensity enables MRCP to be carried out without contrast [5,6]. MRCP is usually performed with heavily T2W sequences by using fat spin echo or SSFSE (Single Shot Fast Spin Echo) technique and both a thick collimation and thin collimation multi section technique with a torso phased array coil.…”

The role of ultrasound in diagnosis of obstructive Jaundice causes in Sudanese population

“…Recent years have witnessed a rapid and continuous evolution in the diagnosis of biliary obstructive disease. Totraditional methodologies, such as US (ultrasonography) ,)CT (computed tomography), ERCP (endoscopic retrograde cholangiopancreatography) and PTC (percutaneous transhepatic cholangiography), there have been added MRCP (magnetic resonance cholagiopancreatography) and CCTcholangio computed tomography), which have prompted a comprehensive review of the whole diagnostic imaging procedure [5][6][7][8][9][10][11][12] .Ultrasound has been always considered the first choice technique in the study of biliary obstructive disease, due to its accessibility, speed, ease of performance and low cost [13,14] . Thishas been even more so in recent years, following the technological evolution of US equipment which, thanks to Tissue Harmonic Imaging (THI), gives better visualization of fluid-filled structures (such as the biliary structures), reduced artifacts, and enhanced contrast resolution [15,16] .ERCP has been considered the gold standard of biliary structureimaging since its introduction in 1970, and is currentlymaintaining its therapeutic application.…”

Stellenwert der Magnetresonanz-Cholangiographie in der rationellen Diagnostik der Choledocholithiasis

“…Da die Echoverzögerungszeit dieser Sequenz bei etwa 1 Sekunde liegt, werden Weichteilgewebe mit T2-Relaxationszeiten eines Bruchteils der Echozeit und schnell fließende Körperflüssigkeiten nicht dargestellt (13,15,32). Zur hochauflösenden und kontrastreichen Darstellung von Weichteilgewebe in einem Atemanhaltezyklus eignet sich unter Verwendung der Half-Fourier-Technik die zeit- optimierte Variante der HASTE-Sequenz (15,22). In großen Serien zur Diagnostik der Choledocholithiasis weist die MRC eine Sensitivität von 57-100% und eine Spezifität von 73-100% auf (10,11,14,15,30,32,35 (11,14).…”