MRCP与ERCP、PTC诊断胆道梗阻性疾病的对比研究

目的 :探讨磁共振胰胆管成像 (MRCP)加梗阻部位薄层扫描或增强扫描、内镜逆行胰胆管造影 (ERCP)、经皮肝穿刺胆道造影 (PTC)对胆道梗阻的诊断价值。材料和方法 :回顾性分析 42例临床怀疑胆道梗阻患者的MRCP资料 (包括薄层或增强扫描 ) ,并与 18例ERCP、9例PTC比较 ,所有病例均经手术病理证实。结果 :MRCP加梗阻部位薄层扫描或增强扫描对胆管梗阻诊断准确率为 90 .5 % ,ERCP为 88.9% ,PTC为 88.9%。结论 :MRCP加梗阻部位薄层扫描或增强扫描对胆管梗阻具有重要诊断价值。     

Clinical impact of MR cholangiopancreatography in patients with biliary disease

PURPOSE: To evaluate the role of MR Cholangiopan-creatography (MRCP) as a first imaging modality in patients with suspected biliary tree pathology and indications to endoscopic retrograde cholangiopancreatography (ERCP). MATERIAL AND METHODS: Eighty-eight patients, with clinical signs of biliary tree pathology underwent MRCP, performed with a 1.5 T unit and a phased-array coil. Surgery, intraoperative cholangiography, percutaneous transhepatic cholangiography (PTC) or ERCP were regarded as the gold standard in patients with obstruction; the remaining patients underwent follow-up MRCP examinations at 6-9 months. The MR examination was performed with baseline T1w 2D FLASH and T2w TSE sequences, followed by the MRCP study (single-slab breath-hold RARE and multislice breath-hold HASTE sequences). The MR images were independently evaluated by two radiologists. RESULTS: MRCP showed normal findings in 20 patients; 68 patients had biliary duct dilatation. In 11 out of 68 patients MRCP did not identify any obstruction (9/11 were true negative cases). A diagnosis of benign obstruction was expressed in 36/59 patients (4 chronic pancreatitis, 29 choledocolithiasis, 4 inflammatory obstruction, 2 primary sclerosing cholangitis), with 1 false positive and 5 false negatives (sensitivity, specificity and diagnostic accuracy of 86%, 95% and 90%, respectively). MRCP identified 23 neoplastic stenoses (20/23 were true positives): the sensitivity, specificity and diagnostic accuracy values were 100%, 87% and 95%, respectively. MRCP correctly identified the level of obstruction in 100% of cases. CONCLUSIONS: MRCP may be considered as a first-step imaging method in patients with clinical signs of biliary disease. The workload of ERCP in the diagnostic stage could therefore be reduced and its use be reserved for therapeutic indications.     

肝外胆管梗阻的磁共振胆胰管造影诊断

目的 评价磁共振胆胰管造影（ＭＲＣＰ）对肝外胆管梗阻性疾病的临床诊断价值。方法 对５４例肝外胆管梗阻性疾病（肝外胆管结石３０例,恶性胆管梗阻２４例）进行ＭＲＣＰ检查,并与临床诊断或手术和病理结果对照分析。ＭＲＣＰ采用不屏气快速自旋回波（ＴＳＥ）序列重工Ｔ２ＷＩ扫描,结合呼吸触发及脂护抑制技术,原始图像以最大信号强度投影（ＭＩＰ）法进行三维重建。结果 全部５４例ＭＲＣＰ检查均一次成功,５２例胆胰管显     

MR cholangiopancreatography (MRCP) at 0.5 T: technique optimisation and preliminary results

The aim of our study was to evaluate the feasibility of MR cholangiopancreatography (MRCP) at 0.5 T. To our knowledge no previous studies of MRCP have been performed at mid-field strength. Thirty-one patients with dilated biliary systems were examined with three-dimensional MRCP. All patients were studied with a 0.5 T superconducting magnet. A three-dimensional turbo spin-echo (TSE) sequence was acquired (TR = 3000 ms, TE = 700 ms, echo train length = 45; acquisition time = 14 min 10 s). Coronal images were post-processed with the MIP algorithm. Recently, the parameters have been optimised (TR = 3000 ms, TE = 700 ms, echo train length =128), reducing the acquisition time to 3 min. Endoscopic retrograde cholangiopancreatography (ERCP) was performed in 26 cases; 5 patients underwent percutaneous transhepatic cholangiography PTC. MRCP and ERCP images were evaluated by an experienced radiologist and an endoscopist. MRCP of diagnostic quality was acquired in all patients. Choledocholithiasis was correctly evaluated by MRCP in 12 of 12 patients, compared with 11 correct diagnoses by ERCP. The presence and the level of the stricture were accurately shown in 16 of 16 patients with MRCP and in 13 of 16 patients with ERCP. The peripheral biliary tree above the obstruction and pancreatic duct were better evaluated by MRCP in all cases. In 3 of 3 patients who had undergone bilio-enteric surgery, a correct evaluation of the site of the anastomosis was possible with MRCP. It is concluded that MRCP performed at mid-field strength allows good visualisation of the dilated biliary system. Excellent results have been obtained on comparison with ERCP. MRCP performed at mid-field strength could have the same clinical value as high field strength MRCP. Correspondence to: P. Pavone     

Magnetic resonance cholangiopancreatography in conjunction with 3D for assessment of different biliary obstruction causes

Objective

To assess the diagnostic value of magnetic resonance imaging in conjunction with 3D-MRCP, with maximum intensity projections and volume rendered images in different biliary obstruction causes.

Patient and methods

This study retrospectively reviewed the radiology records of 29 patients (18 females and 11 males) suffering from obstructive jaundice. All patients were subjected to magnetic resonance imaging (MRI), 3D-MRCP with maximum intensity projection (MIP) and volume rendered (VR) reformatted images for biliary obstruction diseases in Zagazig University Hospitals between November 2008 and January 2010. MR studies were performed with 1.5-T superconductive magnet (Philips Achieva, class II a). The patient ages were ranging from 23 to 66 years (mean age: 34 years). This study was done to evaluate the diagnostic value and accuracy of the new MRI techniques as a non-invasive tool to diagnose and differentiate between benign and malignant variants of biliary obstruction diseases and to facilitate the management planning. All cases were evaluated by clinical examination, laboratory values, grey and colored scale ultrasonography, conventional MRI, three-dimensional (3D-MRCP), MIP, and VR images. Our results were correlated with the histology of the resected specimen, operative (ERCP) or image-guided biopsy in inoperable patients.

Results

The mean age of benign patients was 30 years compared with 54 years in malignant biliary obstruction. Seventeen patients had benign cases 58.6% (6 cases of benign stricture and 11 cases with choledocholithiasis). The other 12 cases had malignant aetiology. Twenty-three patients were subjected to operative procedures, while the remaining six had ERCP/PTC and stenting. The MRI/MRCP images were of good quality in all patients. The intra- and extra-hepatic biliary radicals were visualized completely including the proximal and distal extent of the stricture. Regarding the benign cases (16/17) were satisfactorily diagnosed, however, one case was false negative, due to missed small stone at the MIP reconstructions. The 12 malignant biliary obstruction cases were as follows: five cases were cholangiocarcinoma (one peripheral type, one perihilar position, one Klatskin’s type, and two cases of the distal type), three pancreatic neoplastic lesions, two ampullary carcinoma, and two malignant lymph nodes. Regarding the benign cases 3D-MRCP had 94.1% diagnostic accuracy, otherwise more accuracy reported in malignant causes 100%.

Conclusion

3D-MRCP with MIP creates global images for pancreatico-biliary system. It is as effective as ERCP in detection of biliary obstruction and can precisely determine its level as well. Furthermore, it can provide a road map for management planning. By avoiding the flow artifacts, the false negative results that previously reported in past studies can be reduced.     

磁共振胰胆管造影在肝外胆道梗阻性疾病中的应用价值分析

目的　评价磁共振胆胰管造影 (MRCP)对肝外胆管梗阻性疾病的临床诊断价值。方法　对 2 9例肝外胆管梗阻性疾病 (肝外胆管结石 9例 ,恶性胆管梗阻 18例 ,胆囊周围淋巴结反应性增生 1例 ,胆囊结石 1例 )进行MRCP检查 ,并与术后病理结果或临床综合诊断对照分析。MRCP采用屏气单次激发半数傅立叶变换的TSE序列 (HASTE) ,原始图像以最大信号强度投影 (MIP)法进行三维重建。结果　全部 2 9例MRCP检查均一次成功 ,2 7例胆胰管显示满意。MRCP对肝外胆管梗阻性疾病的定位诊断率为 10 0 % ,定性诊断率为 79.3 %。结论　MRCP检查成功率高 ,对肝外胆管梗阻的定位诊断准确 ,结合原始图像和常规MRI扫描 ,对肝外胆管结石和恶性胆管梗阻的定性诊断也有较高的准确性     

MRCP诊断梗阻性黄疸及其影像学对比研究

目的 探讨MRCP在梗阻性黄疸中的诊断价值。方法 对75例梗阻性黄疸患行MRCP检查，原始图像作三维重建，然后分析其影像表现及诊断结果，并与US、CT和直接胰胆管造影进行比较，对照手术病理结果进行分析结果本组75例中MRCP确诊71例，误诊4例，确诊率95％，与直接胰胆管造影(92％）相近，明显高于US(74％)和CT(75％)。MRCP对梗阻性黄疸定位诊断准确率为100％。结论 MRCP作为无创性检查技术，完整清晰地显示胰胆管系统结构，提高了，梗阻性黄疸的定位和定性诊断率，为临床保守或手术治疗提供可靠依据，可作为梗阻性黄疸患的首选影像学检查方法。     

A prospective comparison of magnetic resonance cholangiopancreatography with endoscopic retrograde cholangiopancreatography in the evaluation of patients with suspected biliary tract disease.

AIM: To determine the diagnostic accuracy of magnetic resonance cholangiopancreatography (MRCP) compared with direct cholangiography in the detection of biliary tract disease. PATIENTS AND METHODS: MRCP was performed in 100 patients in whom direct cholangiographic correlation (ERCP, n = 98; PTC, n = 9; intraoperative cholangiography, n = 3) was available for comparison. The MRCP examinations were performed using a two-dimensional multi-slice, fast spin echo (FSE) technique and a local surface coil. The diagnoses at direct cholangiography were choledocholithiasis in 30 patients, benign and malignant strictures in 28 patients and normal bile ducts in 42 patients. The nature of the strictures (benign, n = 2; tumour, n = 18; lymphnode recurrence, n = 3; unknown histology, n = 5) was determined by one or more of the following procedures: surgery (n = 8), biopsy (n = 15), cytology (n = 6) and cross-sectional imaging/follow-up findings (n = 3). RESULTS: MRCP diagnosed choledocholithiasis with a sensitivity of 93%, specificity of 99% and accuracy of 97 %. It resulted in two false-negative and one false-positive findings when compared with direct cholangiography. MRCP accurately diagnosed the presence and level of strictures in all patients. The overall sensitivity, specificity and accuracy of MRCP in the detection of bile duct lesions were 97%, 98% and 97%, respectively. CONCLUSION: MRCP has a high diagnostic accuracy when compared with direct cholangiography in the detection of bile duct disease.     

ERCP与MRCP对胆道恶性梗阻诊断价值的分析比较

目的比较内镜逆行胰胆管造影(ERCP)和磁共振胰胆管造影(MRCP)对胆道恶性梗阻性疾病的诊断价值。方法对383例胆道梗阻,经手术和(或)ERCP病理证实的142例恶性胆道梗阻患者ERCP和MRCP影像资料进行对比分析。结果MRCP和ERCP总确诊137例恶性梗阻,占96.4%;两种方法定位诊断率分别为92.3%和87.3%;定性诊断率为78.5%和89.8%。结论MRCP在诊断胆道恶性梗阻性疾病方面具有简便安全以及漏诊率低等优点,但误诊率较ERCP高;而ERCP如在诊治过程中与MRCP相结合注重影像学的诊断分析,则可以提高阳性检出率。两者结合使用可起互补作用。     

Pancreaticobiliary diseases. Comparison of 2D single-shot turbo spin-echo MR cholangiopancreatography with endoscopic retrograde cholangiopancreatography

PURPOSE: To compare the diagnostic value of MR cholangiopancreatography (MRCP) to that of endoscopic retrograde cholangiopancreatography (ERCP) in the diagnosis of various obstructive and nonobstructive pancreaticobiliary diseases. MATERIAL AND METHODS: We retrospectively reviewed 153 patients who had undergone both MRCP and ERCP Breath-hold, heavily T2-weighted images using 2D single-shot turbo spin-echo technique were obtained. MRCP and ERCP results were correlated with the final clinical diagnoses. Accuracy of MRCP and ERCP in the diagnosis of pancreaticobiliary diseases, detecting the cause and site of biliary obstruction, if present, and distinguishing malignant from benign cause of obstruction were compared. RESULTS: Success rates of MRCP and ERCP were 98.7% and 89.5%, respectively. The accuracy of MRCP and ERCP in detecting the site of biliary obstruction was 89.7% and 96.2%, and in detecting the cause of biliary obstruction 69.2% and 71.8%, respectively. The sensitivity, specificity and likelihood ratios for positive and negative tests for MRCP and ERCP in distinguishing malignant biliary obstruction from benign causes were 86.4%, 82.4%, 4.9, 0.2 and 88.6%, 94.1%, 15.1, 0.1, respectively. Concordance between the two tests was 91% (kappa coefficient 0.82, standard error of kappa 0.113, p<0.001). In the group of nonobstructive biliary diseases, accuracy of MRCP and ERCP in detecting cholecystolithiasis were 100% and 73.7%, and in detecting pancreatitis 57% and 14%, respectively. CONCLUSION: 2D single-shot turbo spin-echo MRCP can be performed as a complement to ERCP and can replace ERCP in high-risk patients and in case of unsuccessful cannulation.     

Computed tomography and magnetic resonance cholangiography

In patients with biliary obstruction, determining the level and the cause of the obstruction is essential because it can be a key factor for the next step in diagnostic or therapeutic intervention. Noninvasive cholangiography, such as computed tomography (CT) cholangiography or magnetic resonance (MR) cholangiography, allows the diagnosis of cause and level of biliary disease with minimal risk. Traditional magnetic resonance cholangiopancreatography (MRCP) is an established and effective noninvasive diagnostic modality particularly for extrahepatic biliary tract evaluation. Intrahepatic biliary duct evaluation and functional MR, including evaluating for leaks and gallbladder dyskinesia and outlet obstruction, are evolving diagnostic techniques that show promising results. CT cholangiography techniques are especially useful when MRI is not available or contraindicated or when the quality of MRCP images is suboptimal. CT cholangiography is particularly useful as an adjunct to surgery or postsurgical cases. The primary limitation of cholangiographic contrast-enhanced CT cholangiography (the most prevalent type of CT cholangiography) is its hindrance by poor liver function and/or high-grade biliary obstruction. In this setting MRCP is clearly superior. There are different types of CT cholangiography and MRCP. This article discusses the types of CT cholangiography and MRCP techniques and their clinical applications.     

磁共振胆胰管成像(MRCP)与ERCP或PTC临床诊断价值的比较

探讨磁共振胆胰管成像在临床上对不同胆胰管疾病的诊断价值。材料与方法：回顾分析２３例疑有胆囊病患者的ＭＲＣＰ图像，并与其对照的ＥＲＣＰ或ＰＴＣ的诊断结果相比较。ＭＲＣＰ在１．０Ｔ超导磁场中完成，采用快速自旋回波序列ＭＩＰ法重建。结果：２３例患者的ＭＲＣＰ成功率为１００％，１４周手术病例中，ＭＲＣＰ对胆胰管系统非肿瘤性病变和肿瘤性病变的诊断正确率分别为１００％和８３５，１例误诊。     

恶性胆道梗阻的MRCP诊断(附21例分析)

目的　评价MRCP对恶性胆道梗阻的诊断价值。方法　 2 1例经临床及CT发现恶性胆道梗阻者行MRCP检查 ,结合MR平扫及手术病理对照。结果　MRCP对恶性胆道梗阻有较高的诊断率 ,6 8%～ 10 0 %。扩张的肝内胆管呈枯枝样或腊肠样 ,低位梗阻的胆总管末端大多呈截断状、杯口状或鼠尾状。结论　MRCP诊断恶性胆道梗阻准确率高 ,可作为不宜行ERCP的替代检查方法。     

MR cholangiopancreatography: technique, potential indications, and diagnostic features of benign, postoperative, and malignant conditions

The objective of this article is to review technical aspects, discuss potential clinical indications for MR cholangiopancreatography (MRCP) and demonstrate the spectrum of diagnostic findings in benign, postoperative, and malignant conditions. We describe our current imaging protocol in comparison with other available techniques. Using a non-breath-hold, heavily T2-weighted fast-spin-echo (FSE) sequence with or without respiratory gating we obtained coronal and axial source images and maximum intensity projections (MIPs) in 102 patients with suspected abnormalities of the biliary or pancreatic ducts. Based on this series we demonstrate the diagnostic appearance of a variety of benign, postoperative, and malignant conditions of the biliary and pancreatic ducts and discuss potential clinical indications for MRCP. The non-breath-hold FSE technique enables a consistent image quality even in patients who cannot cooperate well. Respiratory gating increased the rate of diagnostic examinations from 79 to 95 %. Acquisition of coronal and axial source images enables detection of bile duct stones as small as 2 mm, although calculi that are impacted and not surrounded by hyperintense bile may sometimes be difficult to detect. The MIP reconstructions help to determine the level of obstruction in malignant jaundice, delineate anatomical variants and malformations, and to diagnose inflammatory conditions, e. g., sclerosing cholangitis, the Mirizzi syndrome and inflammatory changes in the main pancreatic duct. The MRCP technique also correctly demonstrates the morphology of bilio-enteric or bilio-biliary anastomoses. Because MRCP provides sufficient diagnostic information in a wide range of benign and malignant biliary and pancreatic disorders, it could obviate diagnostic endoscopic retrograde cholangiopancreatography (ERCP) in many clinical settings. The ERCP technique may be increasingly reserved for patients in whom nonsurgical interventional procedures are anticipated. Received 25 July 1996; Revision received 1 October 1996; Accepted 5 November 1996     

Malignant hilar and perihilar biliary obstruction: use of MR cholangiography to define the extent of biliary ductal involvement and plan percutaneous interventions.

PURPOSE: To determine the usefulness of magnetic resonance (MR) cholangiography in defining the extent of biliary ductal involvement in patients with malignant hilar and perihilar biliary obstruction and to evaluate whether findings at MR cholangiography alone are sufficient to plan percutaneous interventions in these patients. MATERIALS AND METHODS: Twenty-nine patients with malignant hilar and perihilar biliary obstruction were examined with MR cholangiography. Two radiologists evaluated MR images and determined the extent of biliary ductal involvement. A hypothetical plan for biliary drainage was established prior to any intervention. All patients underwent percutaneous cholangiography, and 27 of 29 patients also underwent biliary drainage and/or stent placement within 7 days after MR cholangiography. By using direct cholangiography as the standard of reference, the usefulness of MR cholangiography in defining the extent of biliary ductal involvement was determined. The type of drainage performed was compared with the type that had been anticipated at MR cholangiography. RESULTS: MR cholangiography was adequate in helping predict the extent of biliary ductal involvement in 28 (96%) of 29 patients and led to underestimation of the extent of the disease in one patient. The therapeutic plan anticipated with MR cholangiography matched the one actually used in 24 (83%) of 29 patients. CONCLUSION: The high accuracy of MR cholangiography for defining extent of ductal involvement in patients with malignant hilar and perihilar obstruction allows adequate planning of percutaneous interventions in a majority of patients.     

Diagnostic accuracy of magnetic resonance cholangiopancreatography and ultrasound compared with direct cholangiography in the detection of choledocholithiasis

AIM: To determine the diagnostic accuracy of magnetic resonance cholangiopancreatography (MRCP) and trans-abdominal ultrasound in the detection of choledocholithiasis, and to compare bile duct stone characteristics using endoscopic retrograde cholangiopancreatography (ERCP), MRCP and ultrasound. MATERIALS AND METHODS: Of 191 consecutive patients referred for diagnostic ERCP, choledocholithiasis was diagnosed in 34 patients using direct cholangiography. The latter took the form of ERCP (n = 29), intraoperative cholangiography (n = 3) or percutaneous transhepatic cholangiography (n = 2). All patients underwent MRCP and ultrasound examinations and their findings for choledocholitiasis were compared with those at direct cholangiography. Finally, in the 29 patients with choledocholithiasis diagnosed under ERCP, stone characteristics were compared across the three investigations of ERCP, MRCP and ultrasound. RESULTS: Compared with direct cholangiography, MRCP showed a sensitivity, specificity and diagnostic accuracy of 91%, 98% and 97%, respectively, in the diagnosis of choledocholithiasis. MRCP resulted in three false-negative and three false-positive findings, four of which occurred due to confusion with lesions at the ampulla. Ultrasound showed a sensitivity, specificity and diagnostic accuracy of 38%, 100% and 89%, respectively, in the diagnosis of choledocholithiasis. ERCP revealed a greater number of stones and these were more proximally distributed within the bile ducts when compared to MRCP. CONCLUSIONS: MRCP is highly accurate in the diagnosis of choloedocholithiasis and has the potential to replace diagnostic ERCP. MRCP underestimates the number of bile duct stones present.     

MR平扫及冠状面LAVA技术在低位胆管梗阻中的诊断价值

目的探讨磁共振平扫[包括磁共振胰胆管造影(MRCP)]及冠状面快速三维容积动态增强(liver acqui-sition with volume acceleration,LAVA)在低位胆管梗阻诊断中的应用价值。资料与方法 64例低位胆管梗阻患者进行MR平扫、MRCP及冠状面LAVA检查,并将检查结果按三种方法分组:(1)平扫(包括MRCP);(2)冠状面LA-VA;(3)MR平扫+冠状面LAVA。对检查结果进行判读与分析,包括病变的定位及定性诊断,并与手术病理、经内镜逆行性胰胆管造影术(ERCP)或经皮肝内胆管造影术(PTC)结果对照,诊断结果进行McNemar检验,数据不足时采用精确概率法。结果依据最终诊断结果将所有病例分为三组:(1)肿瘤性低位胆管梗阻;(2)除结石外良性低位胆管梗阻;(3)结石性低位胆管梗阻。第一组病例中三种方法的定位诊断符合率无统计学差异,而MR平扫的定性诊断符合率低于冠状面LAVA及MR平扫+冠状面LAVA两种方法(P值分别为0.039,0.021)。第二组病例定位及定性诊断符合率无明显统计学差异。第三组冠状面LAVA诊断符合率低于其他两种方法(P=0.031)。结论冠状面LAVA对于肿瘤性低位胆管梗阻的定性诊断具有较大优势,MRCP在胆管梗阻疾病中,简便易行,可用于筛选检查,对于胆管结石的诊断有明显优势。     

Breath-hold magnetic resonance cholangiopancreatography in the evaluation of malignant pancreaticobiliary obstruction

OBJECTIVE: This study was designed to determine the effectiveness of magnetic resonance cholangiopancreatography (MRCP) using a breath-hold single-shot fast spin echo (SSFSE) technique in imaging patients with malignant biliary and/or pancreatic duct obstruction. METHODS: One hundred thirty-one breath-hold MRCP studies in patients with malignant pancreatic and/or biliary obstruction were evaluated. Pathologic diagnoses included pancreatic cancer, biliary malignancy, gallbladder carcinoma, hepatic neoplasms, malignant lymphadenopathy, and ampullary carcinoma. Two observers independently reviewed the images in a blinded fashion to assess the level of obstruction and the site of underlying tumor. RESULTS: The level of obstruction was correctly identified in 104 of 131 cases (79%) by observer 1 and in 107 of 131 cases (82%) by observer 2. The site of underlying tumor was correctly identified in 113 of 131 cases (86%) by observer 1 and in 110 of 131 cases (84%) by observer 2. CONCLUSION: Magnetic resonance cholangiopancreatography utilizing the SSFSE technique can accurately assess the level of obstruction and the site of underlying tumor in patients with malignant pancreaticobiliary obstruction, without the risks of cholangiography. This MRCP technique allows for visualization of intra- and extraductal anatomy and pathology.     

Imaging of the normal and abnormal pancreaticobiliary system with single-shot MR cholangiopancreatography: a pictorial review

Magnetic resonance cholangiopancreatography (MRCP) is a rapidly evolving non-invasive imaging modality that produces images of the pancreatic duct and biliary tree without the need for intravenous or oral contrast. The images are equivalent to those from endoscopic retrograde cholangiopancreatography (ERCP), but the non-invasive acquisition avoids the morbidity and mortality associated with diagnostic ERCP. Magnetic resonance cholangiopancreatography is indicated in patients who require only a diagnostic ERCP, who fail an ERCP or who are unable to undergo ERCP due to altered post-surgical anatomy. Other evolving indications include triaging of patients with obstructive jaundice into percutaneous or endoscopic management drainage pathways depending on the site, length and nature of the duct obstruction, thereby potentially decreasing the number of failed or unsuccessful ERCP. Pre-operative identification of anomalous biliary anatomy and choledocholithiasis prior to laparoscopic cholecystectomy promise to modify the pre-operative and operative management of the patient in order to minimize the risk of duct injury and unnecessary intra-operative dissection and cholangiography. The advantages of the technique include its non-invasiveness, the absence of contrast administration, its relative operator independence and the ability to evaluate both sides of an obstructed duct, thereby accurately evaluating stricture morphology and length. The disadvantages of MRCP compared to ERCP include its lack of an immediate therapeutic solution to duct obstruction, procedural cost, unit availability and the inability to evaluate patients with pacemakers or ferromagnetic implants.     

The diagnostic accuracy of magnetic resonance cholangiopancreatography and ultrasound compared with direct cholangiography in the detection of choledocholithiasis.

AIM: To determine the diagnostic accuracy of magnetic resonance cholangiopancreatography (MRCP) and ultrasound (US) in the diagnosis of choledocholithiasis in a large group of patients with bile duct stones confirmed at direct cholangiography. Also, to compare bile duct stones confirmed at direct cholangiography. Also, to compare bile duct stone characteristics using the three different investigations, endoscopic retrograde cholangiopancreatography (ERCP), MRCP and US. MATERIALS AND METHODS: 191 patients (M:F, 76:115; mean age, 66 years; range, 24-92 years) were investigated by direct cholangiography, MRCP and US. Their final diagnosis as determined at direct cholangiography were choledocholithiasis (n = 34), strictures (n = 47) and normal ducts (n = 110). The direct cholangiographic methods used for diagnosis of choledocholithiasis were ERCP (n = 29), intraoperative cholangiography (n = 3) and percutaneous transhepatic cholangiography (n = 2). The bile duct stone characteristics were compared using ERCP, MRCP and US in the 29 patients in whom stones were exclusively diagnosed by ERCP. RESULTS: Compared with the final diagnosis, MRCP had a sensitivity, specificity and diagnostic accuracy of 91%, 98% and 97%, respectively, in the diagnosis of choledocholithiasis. MRCP resulted in three false-negative and three false-positive findings, four of which occurred due to confusion with lesions at the ampulla. US had a sensitivity, specificity and diagnostic accuracy of 38%, 100% and 89%, respectively, in the diagnosis of choledocholithiasis. ERCP diagnosed more stones and the stones were more proximally distributed within the bile duct at ERCP when compared with MRCP. CONCLUSION: MRCP has a high diagnostic accuracy (97%), similar to that at direct cholangiography, in the diagnosis of choloedocholithiasis. It has the potential to replace diagnostic ERCP and select patients with choledocholithiasis for therapeutic ERCP.